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Organic–inorganic hybrid perovskites based on methylamine lead halide solar cell
Solar Energy 189 (2019) 421–425
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Organic–inorganic hybrid perovskites based on methylamine lead halide solar cell
T
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Ubaid Khana, Yu Zhinonga, , Abbas Ahmad Khanb, Almas Zulfiqarb, Qudrat Ullah khanc a
School of Optics and Photonics, Beijing Engineering Research Center of Mixed Reality and Advanced Display, Beijing Institute of Technology, Beijing 100081, China Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China c College of Physics and Optoelectronics Engeneering, Shenzhen University, Shenzhen 518060, China b
A R T I C LE I N FO
A B S T R A C T
Keywords: Perovskite Solar cells Methylamine lead halide Structure of perovskite
Photovoltaic research has recently attracted great attention. Photovoltaic energy with the solution of methylimine incorporating with lead halide perovskite absorbent has reached the efficiency of almost 21% in configurations of solid state devices, which has replaced traditional dye-sensitized solar cells and evaporated organic solar cells as well as several thin-film photovoltaic films. Due to development in photovoltaic devices and its promising results, interest in this research has been increased. Consequently, it is essential to explain the operational mechanism of solar cells based on perovskite for further development. In this article, we present the structure and the method preparation of methylamine lead halide of organic-inorganic hybrid perovskite and review its current research on the application of solar cells. Meanwhile, the comparative analysis has been made between different points of view and key issues such as the choice of materials, the architecture of the device etc.
1. Introduction Recently, high-efficiency solar cells based on the methylamine lead halide (MLH) of the hybrid inorganic perovskite has been reported (Kim, 2012; Lee, 2012; Burschka, 2013; Liu et al., 2013). Their power conversion efficiency (PCE) progressively has set new records in a past few months, and this is very inspiring for many researchers in this field. MLH has a direct band gap and shows impressive photovoltaic properties, with high extinction coefficient (Kojima, 2012; Radulescu, 2016), bearing mobility (Kagan, 1999; Mitzi, 1995; Khan, 2019; Khan, 2018), width spectrum absorption range (from visible to near light infrared) (Kitazawa et al., 2002) and convenient synthesis method. Thus, its potential application in the optoelectronic field is beyond doubt. Here, we present the structure and preparation of perovskites hybrid organic-inorganic MLH, review its latest research progress in photovoltaic devices, and give a comparative analysis of some disputes. Problems such as the selection of materials, the architecture of the device etc, are essential for further development of MLH solar cells. Photovoltaic energy is a promising green energy technology with ample potential that converts sunlight into electricity. Can contribute significantly to solve the future energy problem. Although highly efficient solar cells already have been marketed based on silicone and
compounds. Semiconductors (Zhang, 2018; Liu, 2019; Lin, 2010), production processes are still comparatively expensive in terms of materials and techniques. Driven by low cost demand, clean, and renewable energy sources, production of photovoltaic is developing. The devices were developed at a rapid pace, most of them. That differs from traditional solar cells in their unique mesoscopic structural characteristics, such as dye-sensitized solar cells (DSSC), quantum dots (Nazeeruddin et al., 2011; Zhang, 2013; Mathew, 2014; Nazeeruddin, 1993) sensitized solar cells (Sargent, 2012), and organic solar cells (Li and Brabec, 2015). 2. Preparation of MLH and structure Family of hybrid perovskites MLH (CH3NH3PbX3), which derives from the structure of the inorganic perovskite AMX3. In which, the halogen anion is represented by X = (I−, Br−, Cl−), the metallic cation Pb2+ corresponds to M the methylamine cations (CH3NH3+) correspond to A. They are form the PbX64− octahedron where Pb2+ is found in centre of the octahedron, and the halogen anion X is found in the 4− corner around CH3NH+ octahedron forms a 3 (Fig. 1(a)). The PbX6 three-dimensional (3D) network of type connected at all angles (Fig. 1(b)). CH3NH3+ is full of the hole between the octahedron and
Abbreviations: DSSC, dye sensitization. Solar cells; MLH, methylamine lead halide; QDSC, quantum dots solar cells; PCE, power conversion efficiency; MMO, mesoporous metal oxide; PHJ, perovskite heterojunction; TSD, two-step deposition ⁎ Corresponding author. E-mail address: [email protected] (Y. Zhinong). https://doi.org/10.1016/j.solener.2019.06.061 Received 13 May 2019; Received in revised form 11 June 2019; Accepted 25 June 2019 0038-092X/ © 2019 Published by Elsevier Ltd on behalf of International Solar Energy Society.
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Fig. 1. (a) Structure of perovskite (b) and their extended network structure connected by the corner-shared octahedra.
chlorine is a result of, for example, different internal electric fields, crystalline orientation or doping (without excluding other possible reasons) it requires more investigation. Also, it was notable that the use of CH3NH3PbBr3 in the sensitizer can obtain a device with higher opencircuit voltage, but short circuit current decreased significantly (Yamanaka, 2018; Kojima, 2009; Brunetti, 2016; Ciccioli and Latini, 2018; McLeod and Liu, 2018; Meng, 2018). Edri et al. CH3NH3PbBr3 used as a sensitizer and got an open-circuit voltage of up to 1.3 V and thought that with a more optimal work function values of the electron and conductors, so much an additional increase in the VOC as enhanced charge separation should be possible (Edri, 2013). Soon after, they used methylamine lead bromide chlorine (CH3NH3PbBr3−xClx) as the absorbent in a mesoporous p-i-n device configuration with VOC 1.5 V (Edri, 2014).
balance the charge of the entire network (Baikie, 2013; Cheng and Lin, 2010; Kawamura et al., 2002). Previous experiments demonstrate that the symmetry and structure of the crystals CH3NH3PbI3 are highly dependent on temperature. Also, the position of the halogen atom X can be replaced by different types of atoms in a given ratio. Randomly, thus forming crystalline materials of mixed organic-inorganic perovskite phase, for example, methylamine lead bromide chloride (CH3NH3PbBr3−xClx) and methylamine lead iodide chlorine (CH3NH3PbI3−xClx). Using this mixing phase, the properties of the material such as band gap can be adjusted or optimized (Kitazawa et al., 2002). 3. Which is the better one materials: I, Br, and Cl In the current dye-sensitized solar cells, it was considered that the selection or optimization of the dye is crucial for the efficiency promotion (Bisquert, 2009), and then MLH were initially used in nanostructured solar cells as one of the most effective sensitizers and exhibit almost ideal light absorption characteristics. In 2009, for the first time, Miyasaka research group present the, perovskite hybrid CH3NH3PbI3 instead of the traditional N719 which is dyed in the DSSC and achieved 3.8% conversion efficiency (Kojima, 2009) within the following 2–3 years, CH3NH3PbI3 as the light collectors in solar cells has led to reports of impressive efficiency values of up to 21% (Brunetti, 2016; Ciccioli and Latini, 2018; McLeod and Liu, 2018; Meng, 2018), so it's a fascinating and important question that what reduce them. It has such unique photoelectric characteristics, using transient femtosecond optical spectroscopy of CH3NH3PbI3 heterojunction with selective extraction of electrons and holes. They have decoupled the dynamics of the electron and the hole and show evidence of long lengths and electron transport holes (both more than 100 nm) and the high PCE of these systems is derived from the comparable optical absorption length and the diffusion lengths of the charge, which transcend the restrictions of traditional semiconductors processed in solution (Xing, 2013). The chloride is incorporated in CH3NH3PbI3 a crystalline CH3NH3PbI3−xClx is formed in the perovskite phase (Lee, 2012). Although the little change in the band gap, both electron and hole diffusion length are > 1 µm; on the contrary, CH3NH3PbI3 shows a comparable effective diffusion length for the holes, however, a shorter one for electrons. It is not clear yet that what reason leads to this, but can be used to explain why CH3NH3PbI3, is used as an absorbent in flat design (for example, without mesoporous scaffolding), has efficiencies of 2–3%, while with possible to reach CH3NH3PbI3−xClx for almost 21%. If the difference between the tri-iodide materials is its counterpart incorporated in
4. Application of methylamine lead halide in solar cell Perovskite solar cells (PSCs) organo-lead halide have aroused as one of the most capable candidates for the next generation of solar cells. Recently, especially during the year of 2012 and 2019, solar cells based on these materials have shown an unprecedented improvement in performance, with an increase in PCE from less than 10% to over 21% (Yamanaka, 2018; Brunetti, 2016; Ciccioli and Latini, 2018; McLeod and Liu, 2018), and this has led to greater research interest despite these remarkable results, various controversies about such perovskitebased solar cells are going, that they involve some crucial factors related to the promotion and device development, and it's urgent and important so that these are clarified. 5. Planar heterojunction or perovskite-sensitized mesostructure structure In general, there are two different device architectures have performed, which correspond to two types of solar energy. Mechanism of cellular functioning and sensitized perovskite planar heterojunction (PHJ). The preceding one possessed a structure of infiltrated mesoporous metal oxide (MMO) with perovskite sensitizer that aims to maximize the interfacial area between two materials, in which the solid state is found. The hole transporter layer (HTL) has been deposited, and it was named mesostructure solar cell (MSSC) (Fig. 2(a)). The latter was built similarly to a planar heterojunction (PHJ)- based on solar cell (PJSC), where the perovskite film was found inserted between selective electrodes and MMO removed (Fig. 2(b)) (Liu et al., 2013). It is rather 422
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Fig. 2. Schematic device configuration of (a) MSSC and (b) PJSC.
clarified the characteristics of the cell. Meanwhile, the cell parameters derived from the model shows that the performance of this PJSC without HTL is comparable to the one of high-efficiency thin film solar cells.
intriguing that the highest reported PCE value of MSSC and PHJ-based solar cells is 19% and 21%, respectively as it looked like MSSC is not inferior to PJSC. In general, however, due to the need for a complex nanostructure in MSSC, this not only leads to the complexity of the process and technology but also cause an excess of energy and material costs. Therefore PJSC is more promising in comparison. While, PJSC also suffers from some serious problems, such as the difficult preparation of thin film perovskite with a good homogeneous effect and total coverage, uncontrollable fluctuations in efficiency etc. Several previous works have reported MLH PJSC with a minimum PCE, but its maximum IPCE can reach 100% in the range of visible light (Ball, 2013; Brunetti, 2016; Ciccioli and Latini, 2018; McLeod and Liu, 2018; Meng, 2018). This implied that the perovskite could probably work well and aim that PHJ architecture is potentially efficient. Eperon et al. analyzed that the poor performance of PJSC could arise by pinhole formation, the incomplete coverage of the perovskite results in a deflection path with low resistance and loss absorption of light in the solar cell (Eperon, 2014), as in other technologies, the problem of film formation is probably extremely important in PHJ (Yang and Loos, 2007). This limitation is mainly found from rigid constraints on the thickness of the film, where the thicker films were too thick for the success of the operation of solar cells. The literature (Eperon, 2014) verified a more efficient PJSC based on CH3NH3PbI3−x Clx (11.4% for the best device) optimizing perovskite coverage and finding the highest levels of efficiency can only be achieved with maximum surface coverage; however, standard deviations are observed. Up to now, almost 50% of the average value. Docampo (2013) show that a PHJ device with the structure of (FTO/PEDOT: PSS/CH3NH3PbI3−x Clx/PCBM/TiOx/Al), It can provide up to 10% PCE. A recent report (Conings, 2014) on manufacturing of solar cells based on mixed metal halide perovskite absorber CH3NH3PbI2Cl, reasonably smooth films with coverage up to > 95% and thicknesses are exceeding 200 nm, which allows close absorption of 100% light and resulting in reproducible efficiency values. Another report (Chen, 2013) has shown the performance of a lowtemperature vapour-assisted solution process. Thin films of polycrystalline perovskite with full surface coverage, reduced surface roughness and grain size up to microscale; and solar cells based on prepared films to reach a PCE of 21%. Flexible PJSC based on MLH was also attempted, and the PCE value was reported by 6% to 9% (Docampo, 2013). So far, the most efficient record of the perovskite PJSC is reported (Brunetti, 2016; Ciccioli and Latini, 2018; McLeod and Liu, 2018; Meng, 2018). Which has PCE of more than 21% and openvoltage of 1.07 V used CH3NH3PbI3−x Clx as an absorbent and manufactured layer by vapour deposited method. Also, some studies have reported a fascinating structure of PJSC based on perovskite, in which the HTL was eliminated, and the level of active perovskite served as hole transporter (Brunetti, 2016; Etgar, 2012). This device without HTL has attracted much attention because it would be advantageous to simplify manufacturing and reduce costs considerably. Meng and his employees have built efficient solar cells TiO2/CH3NH3PbI3/Au with a sequential deposition method and achieved a maximum efficiency of 10.49% (Shi, 2014). They applied the ideal model to a unique PJSC and
6. Preparation method hybrid perovskite Regarding current relationships, MLH preparation methods of the hybrid perovskites mainly involve the evaporation of the solution or the solvent, which has a simple process and easy synthesis. Features ingestion of monocrystalline CH3NH3PbI3 as example, the preparation is as follows (Baikie, 2013) under conditions of ice-water bath (0 °C), slowly add water hydroiodic acid (HI, 40% aqueous solution) to methylamine (CH3NH2, 57% by weight methanol solution), continue stirring for 3 h by sufficient reaction. Heat the mixture to 60 °C on a rotary evaporator, manipulate it with vacuum and crude distillation. The product is obtained (the colour is yellow due to impurities). Then wash for 3 to 6 times with diethyl ether, use filtration by suction, dry under vacuum conditions at 55 °C for 24 h, to obtain white methylamine iodide powder (CH3NH3I) crystalline. Then, weigh the same molar mass of CH3NH3I and PbI2 (99%) in γ -butirolattona to do the reaction enough (60 °C, continuous stirring, 15 h), distribute the solution on the glass substrate, heat to 100 °C and anneal for 40 min and finally, after cooling, CH3NH3PbI3 monocrystalline powder is obtained. Followed by the process similar to this, methylamine lead bromide (CH3NH3PbBr3) and methylamine lead chloride (CH3NH3PbCl3) can be prepared with appropriate hydrohalic acid instead of HI .To prepare the film perovskite MLH (Noh, 2013), four methods have been reported So far (Era, 1997), deposition techniques have been reported in two stages that include coating by centrifugation (Kitazawa, 2004), vacuum depositions and two-step deposition (TSD) vacuum techniques (Liang et al., 1998; Pradeesh et al., 2009; Bi et al., 2013) and patterning thin film (Xia and Whitesides, 1998). Initially, one step rotational coating has been used to manufacture solar cells, but it was difficult to get a high quality film, let alone to obtain an appropriate solvent capable of dissolving both organic moreover, the inorganic part. Also, perovskite particles could not effectively fill the mesoporous metal oxide (MMO), which inevitably led to less absorption of light. Mitzi and collaborators created the TSD technique to prepare the hybrid perovskite when it was used to coat the layers of CH3NH3PbI3, the quality of the film has been greatly improved. Also, The large differences between the devices during the preparation has been reduced (Burschka, 2013). Vacuum evaporation is considered as a good technique for thin films oriented to the layered perovskite stratified with precise control of the film property. However, the preparation of various perovskite using it is expected that the different organic components are limited, and this technique requires a high vacuum, which is also consumes energy and hinders mass production. Many reports recently demonstrates the use of the steam-assisted solution process to make planar and thin-film perovskite films their corresponding solar cells (Chen, 2013). The fundamental step is the film growth through in situ reaction of the PbI2 as-deposited film with CH3NH3I vapor. This process is conceptually different from 423
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2018; Yamanaka, 2018). As for HTL, it must no doubt have possess photoelectric characteristics, meanwhile cost, stability, preparation process etc. should be seriously considered. A variety of organic polymeric materials such as spiro-OMeTAD, poly (3-hexylthiophene-2,5-diyl) (P3HT), poly [N-9hepta-decanyl-2,7-carbazole-alt-3,6-bis(thiophen-5-yl) −2,5- dioctyl2,5-di-hydropyrrolo (Burschka, 2013; Liu et al., 2013)pyrrole-1,4dione] (PCBTDPP), poly- [2,1,3-benzothiadiazol-4,7-diyl [4,4-bis(2ethylhexyl)-4H-cyclopenta 2,1-b: 3,4-b′]dithiophene-2,6-diyl]] (PCPDTBT), poly - [[9- (1-octylnonyl) −9H-carbazole-2,7-diyl]-2,5thiofendiyl-2,1,3-benzothiadiazol-4,7-diyl-2,5-thiophenediyl]) (PCDTBT), poly (triarylamine) (PTAA), 4-(diethylamino) -benzaldehyde diphenylhydracona (DEH), N,N-di-p- methoxyphenylamine-substituted derivatives of pyrene (Py) and cruciform revolving 3.3′-bithiophene (KTM3) were used as HLL (Heo, 2013). However, these holes are also expensive or poor performance. Although some of them reached the maximum PCE (e.g. solar efficiency cells with spiroOMeTAD as HTL have reached almost 21%), it is essential to explore the new HTL for the advancement of cheap and practical perovskite solar cells. Previous work showed that interfacial chemical interactions could play an important role in determining the efficiency in the solid state sensitized solar cells (Brunetti, 2016; Ciccioli and Latini, 2018; Yamanaka, 2018). Also, the design of HTL with the appropriate structure can inhibit the return electron transfer, which will result in a solar cell with a higher fill factor and open circuit voltage. The HTL energy levels are also a methodology for improving the Voc changing the highest molecular full orbital level of HTL to that of lead iodide. The perovskite will result in a greater open circuit potential (Hardin et al., 2012). Previous studies on perovskite solar cells using different HTL indicated that the polyarthrylamine PTAA spiro-OMeTAD, (Heo, 2013) which contain an amine group, the best performance have shown. This has been uncertainty ascribed to the favourable molecular interaction between amine and lead perovskite groups.
the current procedure of the solution and vacuum deposit, avoiding organic and inorganic deposition species. The perovskite film comes from this approach. It has total coverage of the surface, a uniform grain structure with grain size up to micrometers and 100% precursor integrity. 7. What effect on MSSC, MMO and HTL Although MSSC is not that simple and need less manufacturing costs as PJSC, it is necessary to admit that MSSC represents a type of highefficiency architecture. It was believed that the MSSC worked on sensitized mechanisms. Therefore strategies to promote performance for solid-DSSC also adapt to it. Thus, the existing effects of different MMO and HTL in MSSC have become two important aspects of this domain of study. In general, the requirements for an ideal MMO involve reasonable energy band, large specific surface, and high mobility of electrons, easy and low manufacturing cost etc. For the evolution of a solid DSSC, probably the MMO was considered as a scaffold in which it is possible to grow the light absorber MLH and a transporter essential for accepting photoelectrons from the absorber and transporting them to the surface of the electrode, and Titania was studied generally at the beginning (Kim, 2012). Kim et al. synthesized submicron anatase of variable length TiO2 nanorod to replace the porous layer of TiO2, by which is thought to solve the problem that the perovskite particles CH3NH3PbI3 could not effectively fill the MMO, but it does not achieve a higher result (Kim, 2013). Zhao et al. fabricated an MSSC with liquid electrolyte and sensitizer CH3NH3PbI3 (Zhao and Zhu, 2013). They found the characteristics of charge collection and optical absorption. The properties have an evident dependence on the thickness of porous SnO2 film that exerts a significant influence on the current density, the fill factor, photovoltage and the PCE. Biet al. MSSC reported based on ZnO nanorod arrays for the first time, considering that ZnO nanorod aligned vertically the arrays exhibited properties of exclusive materials, as well as easy availability (Bi, 2013). Isolation of Al2O3 was used as MMO, the MSSC resulting in an absorbent layer of CH3NH3PbI2Cl achieved a PCE higher than 10.9% and a VOC higher than 1.1 V (Lee, 2012). This also shows that electrons are capable of transport through the CH3NH3PbI2Cl phase without significant recombination of the charge. A higher electron diffusion rate was found in the CH3NH3PbI2Cl concerning that in mesoporous films of SnO2, revealing that it possesses an ambipolar transport property. The efficiency of the device was further improved to 12.3% by optimizing the thickness of the Al2O3 film layer (Ball, 2013). Carnie et al. proposed an alternative method of deposition of perovskite Al2O3 for which the two-step deposition process can be performed in one step (Carnie, 2013). This has the advantage of combining two production steps in one and negates the need for a sintering step at high temperature (550 °C) and results in devices that have lower embedded energy with a relatively simpler production process. Also, ZrO2 has a larger band gap, and the conduction band is probably much higher in energy than the conduction perovskite band. Therefore, the injection of electrons into them is not possible, and the excited electron remains in the perovskite. Several publications have reported the use of ZrO2 instead of SnO2 can lead to a slightly better result (10.8% instead of 9.5%) (Bi et al., 2013) or significantly worse (4.2% instead of 7.8%) (Kim, 2013) photovoltaic performance. The reason for the different results could be related to the method of deposition of the absorbent, and it is the subject of ongoing research. Also, some MMO with the functionalized structure is also composed. Achieved remarkable performance (Brunetti, 2016; Abrusci, 2013). The successful combination of graphene and CH3NH3PbI3−xClx in MSSC and a remarkable PCE 21% achieved (Brunetti, 2016; Ciccioli and Latini, 2018; Meng, 2018; Yamanaka, 2018). State-of-the-art PSCs based on a mesoporous ZnO scaffold, a CH3NH3PbI3 light-absorption layer and spiro-OMeTAD hole transport layer reached as high as 21% of PCE when measured with AM 1.5G illumination, which is the most effective for the perovskite solar cells reported to date (Brunetti, 2016; Ciccioli and Latini, 2018; Meng,
8. Conclusions In short, we have introduced the structure and preparation of inorganic hybrid MLH (film) perovskite. It is the latest survey on solar cell application, especially compared and analyzed some different points of view and critical issues, including the selection of halogen materials as well as MMO, advantages or disadvantages of two types of architecture device-MSSC and PJSC, effects of HTL diverse or not etc. To conclude, MLH together with them mixed crystals of halides, corresponding to three-dimensional. The perovskite structures have been used as effective light. Harvesters for solar cells, benefiting from the advantages of the direct bandgap, high absorption coefficient and high ambipolar carrier mobility. PJSC has a more promising architecture due to simple manufacturing and lower cost. Meanwhile, it is necessary to admit that MSSC represents a type of high-efficiency device configuration and too soon say that MMO and HTL are necessary or not even though the solar cells based on MLH have reached a PCE almost like as high as 21%, we must keep in mind that these studies are still in the initial phase and that many theoretical and technical questions must be explicit or resolved, as the systematic and complete study of materials. Characteristics and mechanism of operating device stability, (Since perovskite cells contain lead, it is not a critical, poor factor metal but toxic, and should stay out of the environment). Given the relatively short period of time in the development of the perovskite MLH solar cell, and it was widely and intensely researched, we have all the reasons i think the remaining problems, including the reduction of cell area and greater promotion of PCE, will be satisfactorily resolved in the near future and the solar cell MLH- base will undoubtedly have broad application perspectives.
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References
13 (6), 2412–2417. Kitazawa, N., et al., 2004. Optical properties of (C 6 H 5 C 2 H 4 NH 3) 2 PbI 4–x Br x (x= 0–4) mixed-crystal doped PMMA films. J. Mater. Sci. 39 (2), 749–751. Kitazawa, N., Watanabe, Y., Nakamura, Y., 2002. Optical properties of CH 3 NH 3 PbX 3 (X= halogen) and their mixed-halide crystals. J. Mater. Sci. 37 (17), 3585–3587. Kojima, A., et al., 2009. Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. J. Am. Chem. Soc. 131 (17), 6050–6051. Kojima, A., et al., 2012. Highly luminescent lead bromide perovskite nanoparticles synthesized with porous alumina media. Chem. Lett. 41 (4), 397–399. Lee, M.M., et al., 2012. Efficient hybrid solar cells based on meso-superstructured organometal halide perovskites. Science 338 (6107), 643–647. Li, N., Brabec, C.J., 2015. Air-processed polymer tandem solar cells with power conversion efficiency exceeding 10%. Energy Environ. Sci. 8 (10), 2902–2909. Liang, K., Mitzi, D.B., Prikas, M.T., 1998. Synthesis and characterization of organic− inorganic perovskite thin films prepared using a versatile two-step dipping technique. Chem. Mater. 10 (1), 403–411. Lin, C.-H., 2010. Si/Ge/Si double heterojunction solar cells. Thin Solid Films 518 (6), S255–S258. Liu, D., et al., 2019. Improved stability of perovskite solar cells with enhanced moistureresistant hole transport layers. Electrochim. Acta 296, 508–516. Liu, M., Johnston, M.B., Snaith, H.J., 2013. Efficient planar heterojunction perovskite solar cells by vapour deposition. Nature 501 (7467), 395. Mathew, S., et al., 2014. Dye-sensitized solar cells with 13% efficiency achieved through the molecular engineering of porphyrin sensitizers. Nat. Chem. 6 (3), 242. McLeod, J.A., Liu, L., 2018. Prospects for mitigating intrinsic organic decomposition in methylammonium lead triiodide perovskite. J. Phys. Chem. Lett. 9 (9), 2411–2417. Meng, L., et al., 2018. Tailored phase conversion under conjugated polymer enables thermally stable perovskite solar cells with efficiency exceeding 21%. J. Am. Chem. Soc. 140 (49), 17255–17262. Mitzi, D.B., et al., 1995. Transport, optical, and magnetic properties of the conducting halide perovskite CH3NH3SnI3. J. Solid State Chem. 114 (1), 159–163. Nazeeruddin, M.K., et al., 1993. Conversion of light to electricity by cis-X2bis (2, 2'bipyridyl-4, 4'-dicarboxylate) ruthenium (II) charge-transfer sensitizers (X= Cl-, Br-, I-, CN-, and SCN-) on nanocrystalline titanium dioxide electrodes. J. Am. Chem. Soc. 115 (14), 6382–6390. Nazeeruddin, M.K., Baranoff, E., Grätzel, M., 2011. Dye-sensitized solar cells: a brief overview. Sol. Energy 85 (6), 1172–1178. Noh, J.H., et al., 2013. Chemical management for colorful, efficient, and stable inorganic–organic hybrid nanostructured solar cells. Nano Lett. 13 (4), 1764–1769. Pradeesh, K., Baumberg, J., Prakash, G.V., 2009. Exciton switching and Peierls transitions in hybrid inorganic-organic self-assembled quantum wells. Appl. Phys. Lett. 95 (17), 283. Radulescu, M., et al., 2016. Optical and photocatalytic properties of copper (II) doped zinc oxide. Rev. Chim. 67 (12), 2596–2599. Sargent, E.H., 2012. Colloidal quantum dot solar cells. Nat. Photon. 6 (3), 133. Shi, J., et al., 2014. Hole-conductor-free perovskite organic lead iodide heterojunction thin-film solar cells: High efficiency and junction property. Appl. Phys. Lett. 104 (6), 063901. Xia, Y., Whitesides, G.M., 1998. Soft lithography. Angew. Chem. Int. Ed. 37 (5), 550–575. Xing, G., et al., 2013. Long-range balanced electron-and hole-transport lengths in organicinorganic CH3NH3PbI3. Science 342 (6156), 344–347. Yamanaka, S., et al., 2018. Electronic structures and chemical states of methylammonium lead triiodide thin films and the impact of annealing and moisture exposure. J. Appl. Phys. 123 (16), 165501. Yang, X., Loos, J., 2007. Toward high-performance polymer solar cells: the importance of morphology control. Macromolecules 40 (5), 1353–1362. Zhang, S., et al., 2013. Highly efficient dye-sensitized solar cells: progress and future challenges. Energy Environ. Sci. 6 (5), 1443–1464. Zhang, T., et al., 2018. High speed and stable solution-processed triple cation perovskite photodetectors. Adv. Opt. Mater. 6 (13), 1701341. Zhao, Y., Zhu, K., 2013. Charge transport and recombination in perovskite (CH3NH3) PbI3 sensitized TiO2 solar cells. J. Phys. Chem. Lett. 4 (17), 2880–2884.
Abrusci, A., et al., 2013. High-performance perovskite-polymer hybrid solar cells via electronic coupling with fullerene monolayers. Nano Lett. 13 (7), 3124–3128. Baikie, T., et al., 2013. Synthesis and crystal chemistry of the hybrid perovskite (CH 3 NH 3) PbI 3 for solid-state sensitised solar cell applications. J. Mater. Chem. A 1 (18), 5628–5641. Ball, J.M., et al., 2013. Low-temperature processed meso-superstructured to thin-film perovskite solar cells. Energy Environ. Sci. 6 (6), 1739–1743. Bi, D., et al., 2013. Efficient and stable CH 3 NH 3 PbI 3-sensitized ZnO nanorod array solid-state solar cells. Nanoscale 5 (23), 11686–11691. D. Bi et al., RSC Adv. 3 (41), 18762 (2013), 2015. Bisquert, J., et al., 2009. Electron lifetime in dye-sensitized solar cells: theory and interpretation of measurements. J. Phys. Chem. C 113 (40), 17278–17290. Brunetti, B., et al., 2016. On the thermal and thermodynamic (in) stability of methylammonium lead halide perovskites. Sci. Rep. 6, 31896. Burschka, J., et al., 2013. Sequential deposition as a route to high-performance perovskite-sensitized solar cells. Nature 499 (7458), 316. Carnie, M.J., et al., 2013. A one-step low temperature processing route for organolead halide perovskite solar cells. Chem. Commun. 49 (72), 7893–7895. Chen, Q., et al., 2013. Planar heterojunction perovskite solar cells via vapor-assisted solution process. J. Am. Chem. Soc. 136 (2), 622–625. Cheng, Z., Lin, J., 2010. Layered organic–inorganic hybrid perovskites: structure, optical properties, film preparation, patterning and templating engineering. CrystEngComm 12 (10), 2646–2662. Ciccioli, A., Latini, A., 2018. Thermodynamics and the intrinsic stability of lead halide perovskites CH3NH3PbX3. J. Phys. Chem. Lett. 9 (13), 3756–3765. Conings, B., et al., 2014. Perovskite-based hybrid solar cells exceeding 10% efficiency with high reproducibility using a thin film sandwich approach. Adv. Mater. 26 (13), 2041–2046. Docampo, P., et al., 2013. Efficient organometal trihalide perovskite planar-heterojunction solar cells on flexible polymer substrates. Nat. Commun. 4, 2761. Edri, E., et al., 2013. High open-circuit voltage solar cells based on organic–inorganic lead bromide perovskite. J. Phys. Chem. Lett. 4 (6), 897–902. Edri, E., et al., 2014. Chloride inclusion and hole transport material doping to improve methyl ammonium lead bromide perovskite-based high open-circuit voltage solar cells. J. Phys. Chem. Lett. 5 (3), 429–433. Eperon, G.E., et al., 2014. Morphological control for high performance, solution-processed planar heterojunction perovskite solar cells. Adv. Funct. Mater. 24 (1), 151–157. Era, M., et al., 1997. Self-organized growth of PbI-based layered perovskite quantum well by dual-source vapor deposition. Chem. Mater. 9 (1), 8–10. Etgar, L., et al., 2012. Mesoscopic CH3NH3PbI3/TiO2 heterojunction solar cells. J. Am. Chem. Soc. 134 (42), 17396–17399. Hardin, B.E., Snaith, H.J., McGehee, M.D., 2012. The renaissance of dye-sensitized solar cells. Nat. Photon. 6 (3), 162. Heo, J.H., et al., 2013. Efficient inorganic–organic hybrid heterojunction solar cells containing perovskite compound and polymeric hole conductors. Nat. Photon. 7 (6), 486. Kagan, C., 1999. CR Kagan, DB Mitzi, and CD Dimitrakopoulos, Science 286, 945 (1999). Science 286, 945. Kawamura, Y., Mashiyama, H., Hasebe, K., 2002. Structural study on cubic-tetragonal transition of CH 3 NH 3 PbI 3. J. Phys. Soc. Jpn. 71 (7), 1694–1697. Khan, A.A., et al., 2018. Solution processed trilayer structure for high-performance perovskite photodetector. Nanoscale Res. Lett. 13 (1), 399. Khan, U., et al., 2019. High-performance CsPbI 2 Br perovskite solar cells with Zinc and manganese doping. Nanoscale Res. Lett. 14 (1), 116. Kim, H.-S., et al., 2012. Lead iodide perovskite sensitized all-solid-state submicron thin film mesoscopic solar cell with efficiency exceeding 9%. Sci. Rep. 2, 591. Kim, H.-S., et al., 2013. Mechanism of carrier accumulation in perovskite thin-absorber solar cells. Nat. Commun. 4, 2242. Kim, H.-S., et al., 2013. High efficiency solid-state sensitized solar cell-based on submicrometer rutile TiO2 nanorod and CH3NH3PbI3 perovskite sensitizer. Nano Lett.
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Organic–inorganic hybrid perovskites based on methylamine lead halide solar cell
T
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Ubaid Khana, Yu Zhinonga, , Abbas Ahmad Khanb, Almas Zulfiqarb, Qudrat Ullah khanc a
School of Optics and Photonics, Beijing Engineering Research Center of Mixed Reality and Advanced Display, Beijing Institute of Technology, Beijing 100081, China Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China c College of Physics and Optoelectronics Engeneering, Shenzhen University, Shenzhen 518060, China b
A R T I C LE I N FO
A B S T R A C T
Keywords: Perovskite Solar cells Methylamine lead halide Structure of perovskite
Photovoltaic research has recently attracted great attention. Photovoltaic energy with the solution of methylimine incorporating with lead halide perovskite absorbent has reached the efficiency of almost 21% in configurations of solid state devices, which has replaced traditional dye-sensitized solar cells and evaporated organic solar cells as well as several thin-film photovoltaic films. Due to development in photovoltaic devices and its promising results, interest in this research has been increased. Consequently, it is essential to explain the operational mechanism of solar cells based on perovskite for further development. In this article, we present the structure and the method preparation of methylamine lead halide of organic-inorganic hybrid perovskite and review its current research on the application of solar cells. Meanwhile, the comparative analysis has been made between different points of view and key issues such as the choice of materials, the architecture of the device etc.
1. Introduction Recently, high-efficiency solar cells based on the methylamine lead halide (MLH) of the hybrid inorganic perovskite has been reported (Kim, 2012; Lee, 2012; Burschka, 2013; Liu et al., 2013). Their power conversion efficiency (PCE) progressively has set new records in a past few months, and this is very inspiring for many researchers in this field. MLH has a direct band gap and shows impressive photovoltaic properties, with high extinction coefficient (Kojima, 2012; Radulescu, 2016), bearing mobility (Kagan, 1999; Mitzi, 1995; Khan, 2019; Khan, 2018), width spectrum absorption range (from visible to near light infrared) (Kitazawa et al., 2002) and convenient synthesis method. Thus, its potential application in the optoelectronic field is beyond doubt. Here, we present the structure and preparation of perovskites hybrid organic-inorganic MLH, review its latest research progress in photovoltaic devices, and give a comparative analysis of some disputes. Problems such as the selection of materials, the architecture of the device etc, are essential for further development of MLH solar cells. Photovoltaic energy is a promising green energy technology with ample potential that converts sunlight into electricity. Can contribute significantly to solve the future energy problem. Although highly efficient solar cells already have been marketed based on silicone and
compounds. Semiconductors (Zhang, 2018; Liu, 2019; Lin, 2010), production processes are still comparatively expensive in terms of materials and techniques. Driven by low cost demand, clean, and renewable energy sources, production of photovoltaic is developing. The devices were developed at a rapid pace, most of them. That differs from traditional solar cells in their unique mesoscopic structural characteristics, such as dye-sensitized solar cells (DSSC), quantum dots (Nazeeruddin et al., 2011; Zhang, 2013; Mathew, 2014; Nazeeruddin, 1993) sensitized solar cells (Sargent, 2012), and organic solar cells (Li and Brabec, 2015). 2. Preparation of MLH and structure Family of hybrid perovskites MLH (CH3NH3PbX3), which derives from the structure of the inorganic perovskite AMX3. In which, the halogen anion is represented by X = (I−, Br−, Cl−), the metallic cation Pb2+ corresponds to M the methylamine cations (CH3NH3+) correspond to A. They are form the PbX64− octahedron where Pb2+ is found in centre of the octahedron, and the halogen anion X is found in the 4− corner around CH3NH+ octahedron forms a 3 (Fig. 1(a)). The PbX6 three-dimensional (3D) network of type connected at all angles (Fig. 1(b)). CH3NH3+ is full of the hole between the octahedron and
Abbreviations: DSSC, dye sensitization. Solar cells; MLH, methylamine lead halide; QDSC, quantum dots solar cells; PCE, power conversion efficiency; MMO, mesoporous metal oxide; PHJ, perovskite heterojunction; TSD, two-step deposition ⁎ Corresponding author. E-mail address: [email protected] (Y. Zhinong). https://doi.org/10.1016/j.solener.2019.06.061 Received 13 May 2019; Received in revised form 11 June 2019; Accepted 25 June 2019 0038-092X/ © 2019 Published by Elsevier Ltd on behalf of International Solar Energy Society.
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Fig. 1. (a) Structure of perovskite (b) and their extended network structure connected by the corner-shared octahedra.
chlorine is a result of, for example, different internal electric fields, crystalline orientation or doping (without excluding other possible reasons) it requires more investigation. Also, it was notable that the use of CH3NH3PbBr3 in the sensitizer can obtain a device with higher opencircuit voltage, but short circuit current decreased significantly (Yamanaka, 2018; Kojima, 2009; Brunetti, 2016; Ciccioli and Latini, 2018; McLeod and Liu, 2018; Meng, 2018). Edri et al. CH3NH3PbBr3 used as a sensitizer and got an open-circuit voltage of up to 1.3 V and thought that with a more optimal work function values of the electron and conductors, so much an additional increase in the VOC as enhanced charge separation should be possible (Edri, 2013). Soon after, they used methylamine lead bromide chlorine (CH3NH3PbBr3−xClx) as the absorbent in a mesoporous p-i-n device configuration with VOC 1.5 V (Edri, 2014).
balance the charge of the entire network (Baikie, 2013; Cheng and Lin, 2010; Kawamura et al., 2002). Previous experiments demonstrate that the symmetry and structure of the crystals CH3NH3PbI3 are highly dependent on temperature. Also, the position of the halogen atom X can be replaced by different types of atoms in a given ratio. Randomly, thus forming crystalline materials of mixed organic-inorganic perovskite phase, for example, methylamine lead bromide chloride (CH3NH3PbBr3−xClx) and methylamine lead iodide chlorine (CH3NH3PbI3−xClx). Using this mixing phase, the properties of the material such as band gap can be adjusted or optimized (Kitazawa et al., 2002). 3. Which is the better one materials: I, Br, and Cl In the current dye-sensitized solar cells, it was considered that the selection or optimization of the dye is crucial for the efficiency promotion (Bisquert, 2009), and then MLH were initially used in nanostructured solar cells as one of the most effective sensitizers and exhibit almost ideal light absorption characteristics. In 2009, for the first time, Miyasaka research group present the, perovskite hybrid CH3NH3PbI3 instead of the traditional N719 which is dyed in the DSSC and achieved 3.8% conversion efficiency (Kojima, 2009) within the following 2–3 years, CH3NH3PbI3 as the light collectors in solar cells has led to reports of impressive efficiency values of up to 21% (Brunetti, 2016; Ciccioli and Latini, 2018; McLeod and Liu, 2018; Meng, 2018), so it's a fascinating and important question that what reduce them. It has such unique photoelectric characteristics, using transient femtosecond optical spectroscopy of CH3NH3PbI3 heterojunction with selective extraction of electrons and holes. They have decoupled the dynamics of the electron and the hole and show evidence of long lengths and electron transport holes (both more than 100 nm) and the high PCE of these systems is derived from the comparable optical absorption length and the diffusion lengths of the charge, which transcend the restrictions of traditional semiconductors processed in solution (Xing, 2013). The chloride is incorporated in CH3NH3PbI3 a crystalline CH3NH3PbI3−xClx is formed in the perovskite phase (Lee, 2012). Although the little change in the band gap, both electron and hole diffusion length are > 1 µm; on the contrary, CH3NH3PbI3 shows a comparable effective diffusion length for the holes, however, a shorter one for electrons. It is not clear yet that what reason leads to this, but can be used to explain why CH3NH3PbI3, is used as an absorbent in flat design (for example, without mesoporous scaffolding), has efficiencies of 2–3%, while with possible to reach CH3NH3PbI3−xClx for almost 21%. If the difference between the tri-iodide materials is its counterpart incorporated in
4. Application of methylamine lead halide in solar cell Perovskite solar cells (PSCs) organo-lead halide have aroused as one of the most capable candidates for the next generation of solar cells. Recently, especially during the year of 2012 and 2019, solar cells based on these materials have shown an unprecedented improvement in performance, with an increase in PCE from less than 10% to over 21% (Yamanaka, 2018; Brunetti, 2016; Ciccioli and Latini, 2018; McLeod and Liu, 2018), and this has led to greater research interest despite these remarkable results, various controversies about such perovskitebased solar cells are going, that they involve some crucial factors related to the promotion and device development, and it's urgent and important so that these are clarified. 5. Planar heterojunction or perovskite-sensitized mesostructure structure In general, there are two different device architectures have performed, which correspond to two types of solar energy. Mechanism of cellular functioning and sensitized perovskite planar heterojunction (PHJ). The preceding one possessed a structure of infiltrated mesoporous metal oxide (MMO) with perovskite sensitizer that aims to maximize the interfacial area between two materials, in which the solid state is found. The hole transporter layer (HTL) has been deposited, and it was named mesostructure solar cell (MSSC) (Fig. 2(a)). The latter was built similarly to a planar heterojunction (PHJ)- based on solar cell (PJSC), where the perovskite film was found inserted between selective electrodes and MMO removed (Fig. 2(b)) (Liu et al., 2013). It is rather 422
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Fig. 2. Schematic device configuration of (a) MSSC and (b) PJSC.
clarified the characteristics of the cell. Meanwhile, the cell parameters derived from the model shows that the performance of this PJSC without HTL is comparable to the one of high-efficiency thin film solar cells.
intriguing that the highest reported PCE value of MSSC and PHJ-based solar cells is 19% and 21%, respectively as it looked like MSSC is not inferior to PJSC. In general, however, due to the need for a complex nanostructure in MSSC, this not only leads to the complexity of the process and technology but also cause an excess of energy and material costs. Therefore PJSC is more promising in comparison. While, PJSC also suffers from some serious problems, such as the difficult preparation of thin film perovskite with a good homogeneous effect and total coverage, uncontrollable fluctuations in efficiency etc. Several previous works have reported MLH PJSC with a minimum PCE, but its maximum IPCE can reach 100% in the range of visible light (Ball, 2013; Brunetti, 2016; Ciccioli and Latini, 2018; McLeod and Liu, 2018; Meng, 2018). This implied that the perovskite could probably work well and aim that PHJ architecture is potentially efficient. Eperon et al. analyzed that the poor performance of PJSC could arise by pinhole formation, the incomplete coverage of the perovskite results in a deflection path with low resistance and loss absorption of light in the solar cell (Eperon, 2014), as in other technologies, the problem of film formation is probably extremely important in PHJ (Yang and Loos, 2007). This limitation is mainly found from rigid constraints on the thickness of the film, where the thicker films were too thick for the success of the operation of solar cells. The literature (Eperon, 2014) verified a more efficient PJSC based on CH3NH3PbI3−x Clx (11.4% for the best device) optimizing perovskite coverage and finding the highest levels of efficiency can only be achieved with maximum surface coverage; however, standard deviations are observed. Up to now, almost 50% of the average value. Docampo (2013) show that a PHJ device with the structure of (FTO/PEDOT: PSS/CH3NH3PbI3−x Clx/PCBM/TiOx/Al), It can provide up to 10% PCE. A recent report (Conings, 2014) on manufacturing of solar cells based on mixed metal halide perovskite absorber CH3NH3PbI2Cl, reasonably smooth films with coverage up to > 95% and thicknesses are exceeding 200 nm, which allows close absorption of 100% light and resulting in reproducible efficiency values. Another report (Chen, 2013) has shown the performance of a lowtemperature vapour-assisted solution process. Thin films of polycrystalline perovskite with full surface coverage, reduced surface roughness and grain size up to microscale; and solar cells based on prepared films to reach a PCE of 21%. Flexible PJSC based on MLH was also attempted, and the PCE value was reported by 6% to 9% (Docampo, 2013). So far, the most efficient record of the perovskite PJSC is reported (Brunetti, 2016; Ciccioli and Latini, 2018; McLeod and Liu, 2018; Meng, 2018). Which has PCE of more than 21% and openvoltage of 1.07 V used CH3NH3PbI3−x Clx as an absorbent and manufactured layer by vapour deposited method. Also, some studies have reported a fascinating structure of PJSC based on perovskite, in which the HTL was eliminated, and the level of active perovskite served as hole transporter (Brunetti, 2016; Etgar, 2012). This device without HTL has attracted much attention because it would be advantageous to simplify manufacturing and reduce costs considerably. Meng and his employees have built efficient solar cells TiO2/CH3NH3PbI3/Au with a sequential deposition method and achieved a maximum efficiency of 10.49% (Shi, 2014). They applied the ideal model to a unique PJSC and
6. Preparation method hybrid perovskite Regarding current relationships, MLH preparation methods of the hybrid perovskites mainly involve the evaporation of the solution or the solvent, which has a simple process and easy synthesis. Features ingestion of monocrystalline CH3NH3PbI3 as example, the preparation is as follows (Baikie, 2013) under conditions of ice-water bath (0 °C), slowly add water hydroiodic acid (HI, 40% aqueous solution) to methylamine (CH3NH2, 57% by weight methanol solution), continue stirring for 3 h by sufficient reaction. Heat the mixture to 60 °C on a rotary evaporator, manipulate it with vacuum and crude distillation. The product is obtained (the colour is yellow due to impurities). Then wash for 3 to 6 times with diethyl ether, use filtration by suction, dry under vacuum conditions at 55 °C for 24 h, to obtain white methylamine iodide powder (CH3NH3I) crystalline. Then, weigh the same molar mass of CH3NH3I and PbI2 (99%) in γ -butirolattona to do the reaction enough (60 °C, continuous stirring, 15 h), distribute the solution on the glass substrate, heat to 100 °C and anneal for 40 min and finally, after cooling, CH3NH3PbI3 monocrystalline powder is obtained. Followed by the process similar to this, methylamine lead bromide (CH3NH3PbBr3) and methylamine lead chloride (CH3NH3PbCl3) can be prepared with appropriate hydrohalic acid instead of HI .To prepare the film perovskite MLH (Noh, 2013), four methods have been reported So far (Era, 1997), deposition techniques have been reported in two stages that include coating by centrifugation (Kitazawa, 2004), vacuum depositions and two-step deposition (TSD) vacuum techniques (Liang et al., 1998; Pradeesh et al., 2009; Bi et al., 2013) and patterning thin film (Xia and Whitesides, 1998). Initially, one step rotational coating has been used to manufacture solar cells, but it was difficult to get a high quality film, let alone to obtain an appropriate solvent capable of dissolving both organic moreover, the inorganic part. Also, perovskite particles could not effectively fill the mesoporous metal oxide (MMO), which inevitably led to less absorption of light. Mitzi and collaborators created the TSD technique to prepare the hybrid perovskite when it was used to coat the layers of CH3NH3PbI3, the quality of the film has been greatly improved. Also, The large differences between the devices during the preparation has been reduced (Burschka, 2013). Vacuum evaporation is considered as a good technique for thin films oriented to the layered perovskite stratified with precise control of the film property. However, the preparation of various perovskite using it is expected that the different organic components are limited, and this technique requires a high vacuum, which is also consumes energy and hinders mass production. Many reports recently demonstrates the use of the steam-assisted solution process to make planar and thin-film perovskite films their corresponding solar cells (Chen, 2013). The fundamental step is the film growth through in situ reaction of the PbI2 as-deposited film with CH3NH3I vapor. This process is conceptually different from 423
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2018; Yamanaka, 2018). As for HTL, it must no doubt have possess photoelectric characteristics, meanwhile cost, stability, preparation process etc. should be seriously considered. A variety of organic polymeric materials such as spiro-OMeTAD, poly (3-hexylthiophene-2,5-diyl) (P3HT), poly [N-9hepta-decanyl-2,7-carbazole-alt-3,6-bis(thiophen-5-yl) −2,5- dioctyl2,5-di-hydropyrrolo (Burschka, 2013; Liu et al., 2013)pyrrole-1,4dione] (PCBTDPP), poly- [2,1,3-benzothiadiazol-4,7-diyl [4,4-bis(2ethylhexyl)-4H-cyclopenta 2,1-b: 3,4-b′]dithiophene-2,6-diyl]] (PCPDTBT), poly - [[9- (1-octylnonyl) −9H-carbazole-2,7-diyl]-2,5thiofendiyl-2,1,3-benzothiadiazol-4,7-diyl-2,5-thiophenediyl]) (PCDTBT), poly (triarylamine) (PTAA), 4-(diethylamino) -benzaldehyde diphenylhydracona (DEH), N,N-di-p- methoxyphenylamine-substituted derivatives of pyrene (Py) and cruciform revolving 3.3′-bithiophene (KTM3) were used as HLL (Heo, 2013). However, these holes are also expensive or poor performance. Although some of them reached the maximum PCE (e.g. solar efficiency cells with spiroOMeTAD as HTL have reached almost 21%), it is essential to explore the new HTL for the advancement of cheap and practical perovskite solar cells. Previous work showed that interfacial chemical interactions could play an important role in determining the efficiency in the solid state sensitized solar cells (Brunetti, 2016; Ciccioli and Latini, 2018; Yamanaka, 2018). Also, the design of HTL with the appropriate structure can inhibit the return electron transfer, which will result in a solar cell with a higher fill factor and open circuit voltage. The HTL energy levels are also a methodology for improving the Voc changing the highest molecular full orbital level of HTL to that of lead iodide. The perovskite will result in a greater open circuit potential (Hardin et al., 2012). Previous studies on perovskite solar cells using different HTL indicated that the polyarthrylamine PTAA spiro-OMeTAD, (Heo, 2013) which contain an amine group, the best performance have shown. This has been uncertainty ascribed to the favourable molecular interaction between amine and lead perovskite groups.
the current procedure of the solution and vacuum deposit, avoiding organic and inorganic deposition species. The perovskite film comes from this approach. It has total coverage of the surface, a uniform grain structure with grain size up to micrometers and 100% precursor integrity. 7. What effect on MSSC, MMO and HTL Although MSSC is not that simple and need less manufacturing costs as PJSC, it is necessary to admit that MSSC represents a type of highefficiency architecture. It was believed that the MSSC worked on sensitized mechanisms. Therefore strategies to promote performance for solid-DSSC also adapt to it. Thus, the existing effects of different MMO and HTL in MSSC have become two important aspects of this domain of study. In general, the requirements for an ideal MMO involve reasonable energy band, large specific surface, and high mobility of electrons, easy and low manufacturing cost etc. For the evolution of a solid DSSC, probably the MMO was considered as a scaffold in which it is possible to grow the light absorber MLH and a transporter essential for accepting photoelectrons from the absorber and transporting them to the surface of the electrode, and Titania was studied generally at the beginning (Kim, 2012). Kim et al. synthesized submicron anatase of variable length TiO2 nanorod to replace the porous layer of TiO2, by which is thought to solve the problem that the perovskite particles CH3NH3PbI3 could not effectively fill the MMO, but it does not achieve a higher result (Kim, 2013). Zhao et al. fabricated an MSSC with liquid electrolyte and sensitizer CH3NH3PbI3 (Zhao and Zhu, 2013). They found the characteristics of charge collection and optical absorption. The properties have an evident dependence on the thickness of porous SnO2 film that exerts a significant influence on the current density, the fill factor, photovoltage and the PCE. Biet al. MSSC reported based on ZnO nanorod arrays for the first time, considering that ZnO nanorod aligned vertically the arrays exhibited properties of exclusive materials, as well as easy availability (Bi, 2013). Isolation of Al2O3 was used as MMO, the MSSC resulting in an absorbent layer of CH3NH3PbI2Cl achieved a PCE higher than 10.9% and a VOC higher than 1.1 V (Lee, 2012). This also shows that electrons are capable of transport through the CH3NH3PbI2Cl phase without significant recombination of the charge. A higher electron diffusion rate was found in the CH3NH3PbI2Cl concerning that in mesoporous films of SnO2, revealing that it possesses an ambipolar transport property. The efficiency of the device was further improved to 12.3% by optimizing the thickness of the Al2O3 film layer (Ball, 2013). Carnie et al. proposed an alternative method of deposition of perovskite Al2O3 for which the two-step deposition process can be performed in one step (Carnie, 2013). This has the advantage of combining two production steps in one and negates the need for a sintering step at high temperature (550 °C) and results in devices that have lower embedded energy with a relatively simpler production process. Also, ZrO2 has a larger band gap, and the conduction band is probably much higher in energy than the conduction perovskite band. Therefore, the injection of electrons into them is not possible, and the excited electron remains in the perovskite. Several publications have reported the use of ZrO2 instead of SnO2 can lead to a slightly better result (10.8% instead of 9.5%) (Bi et al., 2013) or significantly worse (4.2% instead of 7.8%) (Kim, 2013) photovoltaic performance. The reason for the different results could be related to the method of deposition of the absorbent, and it is the subject of ongoing research. Also, some MMO with the functionalized structure is also composed. Achieved remarkable performance (Brunetti, 2016; Abrusci, 2013). The successful combination of graphene and CH3NH3PbI3−xClx in MSSC and a remarkable PCE 21% achieved (Brunetti, 2016; Ciccioli and Latini, 2018; Meng, 2018; Yamanaka, 2018). State-of-the-art PSCs based on a mesoporous ZnO scaffold, a CH3NH3PbI3 light-absorption layer and spiro-OMeTAD hole transport layer reached as high as 21% of PCE when measured with AM 1.5G illumination, which is the most effective for the perovskite solar cells reported to date (Brunetti, 2016; Ciccioli and Latini, 2018; Meng,
8. Conclusions In short, we have introduced the structure and preparation of inorganic hybrid MLH (film) perovskite. It is the latest survey on solar cell application, especially compared and analyzed some different points of view and critical issues, including the selection of halogen materials as well as MMO, advantages or disadvantages of two types of architecture device-MSSC and PJSC, effects of HTL diverse or not etc. To conclude, MLH together with them mixed crystals of halides, corresponding to three-dimensional. The perovskite structures have been used as effective light. Harvesters for solar cells, benefiting from the advantages of the direct bandgap, high absorption coefficient and high ambipolar carrier mobility. PJSC has a more promising architecture due to simple manufacturing and lower cost. Meanwhile, it is necessary to admit that MSSC represents a type of high-efficiency device configuration and too soon say that MMO and HTL are necessary or not even though the solar cells based on MLH have reached a PCE almost like as high as 21%, we must keep in mind that these studies are still in the initial phase and that many theoretical and technical questions must be explicit or resolved, as the systematic and complete study of materials. Characteristics and mechanism of operating device stability, (Since perovskite cells contain lead, it is not a critical, poor factor metal but toxic, and should stay out of the environment). Given the relatively short period of time in the development of the perovskite MLH solar cell, and it was widely and intensely researched, we have all the reasons i think the remaining problems, including the reduction of cell area and greater promotion of PCE, will be satisfactorily resolved in the near future and the solar cell MLH- base will undoubtedly have broad application perspectives.
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References
13 (6), 2412–2417. Kitazawa, N., et al., 2004. Optical properties of (C 6 H 5 C 2 H 4 NH 3) 2 PbI 4–x Br x (x= 0–4) mixed-crystal doped PMMA films. J. Mater. Sci. 39 (2), 749–751. Kitazawa, N., Watanabe, Y., Nakamura, Y., 2002. Optical properties of CH 3 NH 3 PbX 3 (X= halogen) and their mixed-halide crystals. J. Mater. Sci. 37 (17), 3585–3587. Kojima, A., et al., 2009. Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. J. Am. Chem. Soc. 131 (17), 6050–6051. Kojima, A., et al., 2012. Highly luminescent lead bromide perovskite nanoparticles synthesized with porous alumina media. Chem. Lett. 41 (4), 397–399. Lee, M.M., et al., 2012. Efficient hybrid solar cells based on meso-superstructured organometal halide perovskites. Science 338 (6107), 643–647. Li, N., Brabec, C.J., 2015. Air-processed polymer tandem solar cells with power conversion efficiency exceeding 10%. Energy Environ. Sci. 8 (10), 2902–2909. Liang, K., Mitzi, D.B., Prikas, M.T., 1998. Synthesis and characterization of organic− inorganic perovskite thin films prepared using a versatile two-step dipping technique. Chem. Mater. 10 (1), 403–411. Lin, C.-H., 2010. Si/Ge/Si double heterojunction solar cells. Thin Solid Films 518 (6), S255–S258. Liu, D., et al., 2019. Improved stability of perovskite solar cells with enhanced moistureresistant hole transport layers. Electrochim. Acta 296, 508–516. Liu, M., Johnston, M.B., Snaith, H.J., 2013. Efficient planar heterojunction perovskite solar cells by vapour deposition. Nature 501 (7467), 395. Mathew, S., et al., 2014. Dye-sensitized solar cells with 13% efficiency achieved through the molecular engineering of porphyrin sensitizers. Nat. Chem. 6 (3), 242. McLeod, J.A., Liu, L., 2018. Prospects for mitigating intrinsic organic decomposition in methylammonium lead triiodide perovskite. J. Phys. Chem. Lett. 9 (9), 2411–2417. Meng, L., et al., 2018. Tailored phase conversion under conjugated polymer enables thermally stable perovskite solar cells with efficiency exceeding 21%. J. Am. Chem. Soc. 140 (49), 17255–17262. Mitzi, D.B., et al., 1995. Transport, optical, and magnetic properties of the conducting halide perovskite CH3NH3SnI3. J. Solid State Chem. 114 (1), 159–163. Nazeeruddin, M.K., et al., 1993. Conversion of light to electricity by cis-X2bis (2, 2'bipyridyl-4, 4'-dicarboxylate) ruthenium (II) charge-transfer sensitizers (X= Cl-, Br-, I-, CN-, and SCN-) on nanocrystalline titanium dioxide electrodes. J. Am. Chem. Soc. 115 (14), 6382–6390. Nazeeruddin, M.K., Baranoff, E., Grätzel, M., 2011. Dye-sensitized solar cells: a brief overview. Sol. Energy 85 (6), 1172–1178. Noh, J.H., et al., 2013. Chemical management for colorful, efficient, and stable inorganic–organic hybrid nanostructured solar cells. Nano Lett. 13 (4), 1764–1769. Pradeesh, K., Baumberg, J., Prakash, G.V., 2009. Exciton switching and Peierls transitions in hybrid inorganic-organic self-assembled quantum wells. Appl. Phys. Lett. 95 (17), 283. Radulescu, M., et al., 2016. Optical and photocatalytic properties of copper (II) doped zinc oxide. Rev. Chim. 67 (12), 2596–2599. Sargent, E.H., 2012. Colloidal quantum dot solar cells. Nat. Photon. 6 (3), 133. Shi, J., et al., 2014. Hole-conductor-free perovskite organic lead iodide heterojunction thin-film solar cells: High efficiency and junction property. Appl. Phys. Lett. 104 (6), 063901. Xia, Y., Whitesides, G.M., 1998. Soft lithography. Angew. Chem. Int. Ed. 37 (5), 550–575. Xing, G., et al., 2013. Long-range balanced electron-and hole-transport lengths in organicinorganic CH3NH3PbI3. Science 342 (6156), 344–347. Yamanaka, S., et al., 2018. Electronic structures and chemical states of methylammonium lead triiodide thin films and the impact of annealing and moisture exposure. J. Appl. Phys. 123 (16), 165501. Yang, X., Loos, J., 2007. Toward high-performance polymer solar cells: the importance of morphology control. Macromolecules 40 (5), 1353–1362. Zhang, S., et al., 2013. Highly efficient dye-sensitized solar cells: progress and future challenges. Energy Environ. Sci. 6 (5), 1443–1464. Zhang, T., et al., 2018. High speed and stable solution-processed triple cation perovskite photodetectors. Adv. Opt. Mater. 6 (13), 1701341. Zhao, Y., Zhu, K., 2013. Charge transport and recombination in perovskite (CH3NH3) PbI3 sensitized TiO2 solar cells. J. Phys. Chem. Lett. 4 (17), 2880–2884.
Abrusci, A., et al., 2013. High-performance perovskite-polymer hybrid solar cells via electronic coupling with fullerene monolayers. Nano Lett. 13 (7), 3124–3128. Baikie, T., et al., 2013. Synthesis and crystal chemistry of the hybrid perovskite (CH 3 NH 3) PbI 3 for solid-state sensitised solar cell applications. J. Mater. Chem. A 1 (18), 5628–5641. Ball, J.M., et al., 2013. Low-temperature processed meso-superstructured to thin-film perovskite solar cells. Energy Environ. Sci. 6 (6), 1739–1743. Bi, D., et al., 2013. Efficient and stable CH 3 NH 3 PbI 3-sensitized ZnO nanorod array solid-state solar cells. Nanoscale 5 (23), 11686–11691. D. Bi et al., RSC Adv. 3 (41), 18762 (2013), 2015. Bisquert, J., et al., 2009. Electron lifetime in dye-sensitized solar cells: theory and interpretation of measurements. J. Phys. Chem. C 113 (40), 17278–17290. Brunetti, B., et al., 2016. On the thermal and thermodynamic (in) stability of methylammonium lead halide perovskites. Sci. Rep. 6, 31896. Burschka, J., et al., 2013. Sequential deposition as a route to high-performance perovskite-sensitized solar cells. Nature 499 (7458), 316. Carnie, M.J., et al., 2013. A one-step low temperature processing route for organolead halide perovskite solar cells. Chem. Commun. 49 (72), 7893–7895. Chen, Q., et al., 2013. Planar heterojunction perovskite solar cells via vapor-assisted solution process. J. Am. Chem. Soc. 136 (2), 622–625. Cheng, Z., Lin, J., 2010. Layered organic–inorganic hybrid perovskites: structure, optical properties, film preparation, patterning and templating engineering. CrystEngComm 12 (10), 2646–2662. Ciccioli, A., Latini, A., 2018. Thermodynamics and the intrinsic stability of lead halide perovskites CH3NH3PbX3. J. Phys. Chem. Lett. 9 (13), 3756–3765. Conings, B., et al., 2014. Perovskite-based hybrid solar cells exceeding 10% efficiency with high reproducibility using a thin film sandwich approach. Adv. Mater. 26 (13), 2041–2046. Docampo, P., et al., 2013. Efficient organometal trihalide perovskite planar-heterojunction solar cells on flexible polymer substrates. Nat. Commun. 4, 2761. Edri, E., et al., 2013. High open-circuit voltage solar cells based on organic–inorganic lead bromide perovskite. J. Phys. Chem. Lett. 4 (6), 897–902. Edri, E., et al., 2014. Chloride inclusion and hole transport material doping to improve methyl ammonium lead bromide perovskite-based high open-circuit voltage solar cells. J. Phys. Chem. Lett. 5 (3), 429–433. Eperon, G.E., et al., 2014. Morphological control for high performance, solution-processed planar heterojunction perovskite solar cells. Adv. Funct. Mater. 24 (1), 151–157. Era, M., et al., 1997. Self-organized growth of PbI-based layered perovskite quantum well by dual-source vapor deposition. Chem. Mater. 9 (1), 8–10. Etgar, L., et al., 2012. Mesoscopic CH3NH3PbI3/TiO2 heterojunction solar cells. J. Am. Chem. Soc. 134 (42), 17396–17399. Hardin, B.E., Snaith, H.J., McGehee, M.D., 2012. The renaissance of dye-sensitized solar cells. Nat. Photon. 6 (3), 162. Heo, J.H., et al., 2013. Efficient inorganic–organic hybrid heterojunction solar cells containing perovskite compound and polymeric hole conductors. Nat. Photon. 7 (6), 486. Kagan, C., 1999. CR Kagan, DB Mitzi, and CD Dimitrakopoulos, Science 286, 945 (1999). Science 286, 945. Kawamura, Y., Mashiyama, H., Hasebe, K., 2002. Structural study on cubic-tetragonal transition of CH 3 NH 3 PbI 3. J. Phys. Soc. Jpn. 71 (7), 1694–1697. Khan, A.A., et al., 2018. Solution processed trilayer structure for high-performance perovskite photodetector. Nanoscale Res. Lett. 13 (1), 399. Khan, U., et al., 2019. High-performance CsPbI 2 Br perovskite solar cells with Zinc and manganese doping. Nanoscale Res. Lett. 14 (1), 116. Kim, H.-S., et al., 2012. Lead iodide perovskite sensitized all-solid-state submicron thin film mesoscopic solar cell with efficiency exceeding 9%. Sci. Rep. 2, 591. Kim, H.-S., et al., 2013. Mechanism of carrier accumulation in perovskite thin-absorber solar cells. Nat. Commun. 4, 2242. Kim, H.-S., et al., 2013. High efficiency solid-state sensitized solar cell-based on submicrometer rutile TiO2 nanorod and CH3NH3PbI3 perovskite sensitizer. Nano Lett.
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