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A comparative study of different ETMs in perovskite solar cell with inorganic copper iodide as HTM
Accepted Manuscript Title: A Comparative Study of Different ETMs in Perovskite Solar Cell with Inorganic Copper Iodide as HTM Authors: Mostafa M Salah, Kamel M. Hassan, Mohamed Abouelatta, Ahmed Shaker PII: DOI: Reference:
S0030-4026(18)31551-1 https://doi.org/10.1016/j.ijleo.2018.10.052 IJLEO 61677
To appear in: Received date: Accepted date:
19-8-2018 8-10-2018
Please cite this article as: Salah MM, Hassan KM, Abouelatta M, Shaker A, A Comparative Study of Different ETMs in Perovskite Solar Cell with Inorganic Copper Iodide as HTM, Optik (2018), https://doi.org/10.1016/j.ijleo.2018.10.052 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
A Comparative Study of Different ETMs in Perovskite
SC RI PT
Solar Cell with Inorganic Copper Iodide as HTM
Mostafa M Salah1, Kamel M. Hassan1, Mohamed Abouelatta2 and Ahmed Shaker2,*
Faculty of Engineering and Technology, Future University, Cairo, Egypt
2
Faculty of Engineering, Ain Shams University, Cairo, Egypt
author. E-mail address: [email protected] (Ahmed Shaker).
M
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*Corresponding
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Abstract
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Perovskite solar cells (PSCs) research is substantially increasing because of the fast
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improvement in their power conversion efficiency (PCE), cheapness, possibility to tune the bandgap, low recombination rate, high open circuit voltage, excellent ambipolar charge carrier
EP
transport and strong and broad optical absorption. In this paper, different electron transport
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materials (ETMs) have been analyzed with a new Copper Iodide (CuI) Hole Transport Material (HTM) to replace the conventional hole and electron transport materials for PSCs, such as TiO2
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and Spiro-OMeTAD which have been known to be susceptible to light induced degradation. Moreover, the influence of the ETL, HTL and the perovskite layer thicknesses on the overall cell performance, is studied. The design of the proposed PSC is performed utilizing SCAPS-1D simulator (Solar Cell Capacitance Simulator-one dimension). Because of its high electron affinity and tunable bandgap, ZnOS is found to be the best replacement for TiO2. The results show that 1
lead-based PSC with CuI as HTM is an efficient arrangement and better than the easily degradable and expensive Spiro-OMeTAD. According to the presented simulation and optimization of various
SC RI PT
layers thicknesses, the highest designed efficiency is 26.11%.
Keywords — Perovskite Solar Cell (PSC); Hole transport materials (HTMs); Electron transport materials (ETMs); SCAPS-1D; copper iodide.
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1. Introduction
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Nowadays, Solar is the most natural sources commonly used for renewable energy.
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Crystalline silicon offers PCEs of up to around 25%; however, the manufacturing of such solar
M
cells is quite costly. For these reasons, new PV technologies based on simple preparation procedures and abundant and cheap materials are required [1]. Lead-based PSCs have gained a
D
significant attention due to their lower cost and simpler fabrication techniques as opposed to
TE
conventional silicon solar cells [2]. PSCs are made from organic-inorganic materials of methyl ammonium lead halides (CH3NH3PbX3, where X = I, Br, or Cl) by different techniques and
EP
structures such as vacuum evaporation and solution schemes, and with planar and mesoporous
CC
heterojunction structures [3]. The PCE of PSCs has improved from 3.8% in 2009 to more than 22% in 2016 [4, 5]. Their success is primarily because of their unique set of electronic properties,
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such as ambipolar transport properties, micrometer to millimeter charge carrier diffusion lengths, low intrinsic recombination rates, tunable band gaps across the visible region, and large absorption coefficients. In addition to their unique set of electronic properties, low cost techniques for their deposition and synthesis, or alternatively to vapor deposition methods are utilized. These properties make the PSCs one of the best solar cells encountered. 2
CuI shows electrical conductivity two orders higher than Spiro-MeOTAD that allowed higher fill factor (FF) as determined by impedance spectroscopy [6]. Notably, this impressive electrical conductivity is coupled to a low cost, excellent ambient stability, hydrophobic nature,
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wide band gap and solution processability make CuI a very promising HTM material [7]. Initially, PSC with CuI as HTL achieved PCE of 6% [8]. Recently, PCE achieved 17.6% when CuI films were fabricated by facile spray deposition [9]. To study types of these promising cells, simulations are used extensively and one of the most programs used, in this regard, is SCAPS [10]. In this paper, SCAPS is utilized for the simulation of lead-based CH3NH3PbI3 PSCs with
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CuI as HTM and TiO2, CdS, ZnSe, ZnO, and ZnOS as ETMs to assess promising replacements to
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TiO2 and Spiro-OMeTAD for CH3NH3PbI3 PSCs. Two interface layers were also used to make
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the device more practical, each with a thickness of 10 nm. The interface layers were incorporated
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at the HTL/CH3NH3PbX3 interface and at the ETL/CH3NH3PbX3 interface. Furthermore, we
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compared the short circuit current density, open circuit voltage, FF and PCE of the PSCs and
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approved Spiro-MeOTAD and TiO2 be substituted for other materials and that give better performance. The proposed CuI/ZnOS cell grasps the highest PCE of 23.47%. Finally, after
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performing some optimization on the thickness of the absorber layer, HTL, and ETL an efficiency
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of 26.11% is obtained.
2. Modeling and Simulation
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The design of the proposed perovskite p-i-n device structure and the energy band diagram
are illustrated in Figure 1. The proposed structure is comprised of glass substrate / transparent conducting oxide (TCO) / ETL / interface defect layer (IDL) / CH3NH3PbI3 / interface defect layer (IDL) / CuI (HTL) / metal back contact. We have simulated IV n-type materials as ETL for CH3NH3PbI3 PSCs with CuI as HTL. Table 1 indicates the values of the parameters used in the 3
simulation. Table 2 shows the defect properties and their parameters. The flat band model is used for the semiconductor/TCO and semiconductor/metal interfaces. For the parameters not exist in table 1 and 2, the following values were used for all layers: thermal velocity of electrons and holes
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of 107 cm/s [9], neutral defects at the center of the bandgap with a Gaussian distribution, characteristic energy of 0.1 eV, and defect density of 1015 [14]. The absorption coefficient (α) of ETMs, TCO, and CuI was calculated via Equation (1) with the pre-factor (Aα) assumed to be 105 m-1 [11].
(1)
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𝛼(𝐸) = 𝐴𝛼 (ℎν − 𝐸𝑔 )0.5
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Figure 1. Device structure and energy band diagram
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3. Results and Discussion A. CuI as HTM with different ETM Figure 2 shows simulated J-V curves for a CH3NH3PbI3 based device in the n-i-p configuration with CuI as HTL, TiO2, CdS, ZnSe, ZnO, and ZnOS as ETLs. CuI/ZnOS cell has reached the highest PCE of 23.47% with the highest open circuit voltage (Voc) of 1.24 V, current 4
density (Jsc) of 21.524 mA/cm2 and highest FF of 87.85%. CuI/ZnO, CuI/ TiO2 has the same Voc of 1.155 V with very close Jsc of 21.553 mA/cm2, 21.529 mA/cm2, almost same FF of 87.5%, 87.51% and power conversion efficiency of 21.76% and 21.79%, respectively. CuI/CdS cell has
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achieved high PCE of 21.9% with high open circuit voltage (Voc) of 1.231 V, current density (Jsc) of 21.553 mA/cm2 and FF of 82.53%. CuI/ZnSe cell has Voc of 1.128 V with current density (Jsc) of 21.554 mA/cm2 with an efficiency of 19.76% and FF of 81.19%. A comparison of the simulated values of Jsc, Voc, FF, and power conversion efficiency is given in Table 3. Figure 3 shows the quantum efficiency (QE) of the five cells. In SCAPS, QE is the external quantum efficiency (EQE).
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The figure demonstrates that all cells show similar QE curve with minimal differences.
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Fig. 2. J-V curves for CH3NH3PbI3 based solar cells with TiO2, CdS, ZnSe, ZnO, and ZnOS.
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Fig. 3. Quantum efficiency curves for CH3NH3PbI3 based solar cells with TiO2, CdS, ZnSe, ZnO,
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and ZnOS.
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B. Influence of thickness of absorber layer
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From the previous section, we get the best performance of CuI/ZnOS cell with PCE of 23.47%. Now we will optimize the thickness of ETM, HTM, and the absorber layer of this cell to
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obtain better performance. H. Anwar [7] has shown an optimum thickness of 600 nm for the absorber layer. We get a PCE of 25.96% which increased by 2.49%, FF of 87.82%, Voc of 1.2439
CC
V, and Jsc of 23.766 mA/cm2 when we make the thickness of the absorber layer 600 nm.
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C. Influence of thickness of ETM Next, Figure 4 shows the influence of the thickness of ETM on the performance parameters
of the cell when the thickness of the absorber layer is 600 nm. We get the best performance when the thickness of ETM is 30 nm with highest PCE of 25.98% which increased by 0.02%, same FF of 87.82%, same Voc of 1.2439 V, and Jsc of 23.778 mA/cm2. 6
D. Influence of thickness of HTM Moreover, Figure 5 shows the influence of the thickness of HTM on performance parameters of the cell when the thickness of the absorber layer is 600 nm. The performance of the
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cell is inversely proportional to the thickness of HTM. We choose a thickness of 30 nm like the ETM and we get PCE of 26.1% which increased by 0.05%, same FF of 88.29%, same Voc of 1.2439
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V, and Jsc of 23.766 mA/cm2.
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Fig. 4. Variation in performance parameters depending on the variation of the thickness of ETM.
Fig. 5. Variation in performance parameters depending on the variation of the thickness of HTM. 7
Finally, examining the thickness of all layers, we obtained encouraging results, Jsc of 23.778 mA/cm2, Voc of 1.2439 V, FF of 87.96%, and PCE of 26.11%. Figure 6 and Figure 7 indicate the JV and QE respectively of the CuI/ZnOS cell before and after optimization of the
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thickness in the absorber layer, ETM, and HTM. Further, Table 4 displays a comparison between
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our simulated results with the experimental work by the other researchers.
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Fig. 6. J-V curves for CuI/ZnOS cell before and after optimizing the thickness.
Fig. 7. QE curves for CuI/ZnOS cell before and after optimizing the thickness.
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4. Conclusion Lead-based CH3NH3PbI3 PSC with CuI as HTM and different ETMs are studied by SCAPS simulation. The results show that CuI as alternate HTM has the potential to be used with perovskite
SC RI PT
absorber and can replace the Spiro-MeTAD which is expensive and suffers from degradation. ZnOS is the best ETL material to replace TiO2. The highest PCE achieved is 23.47%. The thickness of the layers has a great influence on the performance parameters of the solar cells. After
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optimizing the thickness of all the layers, we get a PCE of 26.11%.
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5. Acknowledgment
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We would like to express sincere thanks to Dr. Marc Burgelman, Department of Electronics
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and Information Systems (ELIS), University of Gent, Belgium, for providing the SCAPS-1D
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simulation tool.
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References
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[10] Burgelman, Marc, Koen Decock, Samira Khelifi, and Aimi Abass. "Advanced electrical
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lead based perovskite solar cell using SCAPS-1D." Indian Journal of Science and
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[12] Bansal, Shubhra, and Puruswottam Aryal. "Evaluation of new materials for electron and hole transport layers in perovskite-based solar cells through SCAPS-1D simulations."
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[24] Gloeckler, Markus. "Device physics of Cu (In, Ga) Se2 thin-film solar cells." PhD diss.,
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Colorado State University, 2005.
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[27] Sepalage, Gaveshana A., Steffen Meyer, Alexander Pascoe, Andrew D. Scully, Fuzhi Huang, Udo Bach, Leone Spiccia, and Yi‐ Bing Cheng. "Copper (I) iodide as hole‐ conductor in
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Table
Table 1 Simulation Parameters of PSCs Devices IDL
CH3NH3PbI3
CuI
TiO2
Thickness (nm)
500
10
350
100
50
Band gap energy Eg (eV)
3.5
1.55
1.55[12]
2.98[16]
3[20]
Electron affinity χ (eV)
4
3.9
3.9[12]
2.1[17]
4[21]
Relative permittivity ɛr
9
18
18[13]
6.5[18]
9[22]
Effective conduction band density Nc (cm-3)
2.2E+18
2.2E+18
2.2E+18
2.8E+19
2.2E+18
Effective valence band density Nv (cm3)
1.9E+19
1.9E+19
1.9E+19
1E+19
20
3
3[13]
1.69E-4
8
17
17[13]
ZnSe
ZnO
ZnOS
50
50
50
2.4[14]
2.81[12]
3.3[23]
2.83[24]
4.18[14]
4.09[12]
4[23]
3.6[24]
10[14]
8.6[12]
9[23]
9[24]
2.2E+18
2.2E+18
2.2E+18
2.2E+18[24]
1.9E+19
1.9E+19
1.9E+19
1.8E+19[24]
2[20]
100[14]
400[12]
100[23]
100[24]
1.69E-4
1[20]
25[14]
110[12]
25[23]
25[24]
1E+13[15]
0
1E+18
1E+18
1E+18
1E+18
2E+18[24]
0
1E+18[19]
0
0
0
0
0
U
50
Hole mobility µp
Donor concentration ND (cm-3)
1E+13
CC
EP
1E+18
0
A
TE
(cm-2 V-1 S-1)
D
(cm-2 V-1 S-1)
0
1.9E+19
M
Electron mobility µe
Acceptor concentration NA (cm-3)
CdS
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TCO
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Parameters
Table 2 Defect parameters of PSCs Devices TCO
IDL
CH3NH3PbI3
CuI
TiO2
CdS
ZnO
ZnOS
Electrons capture cross section (cm²)
2E-14
2E-14
2E-14
2E-14
2E-14
2E-14
2E-14
1E-15
Holes capture cross section (cm²)
2E-14
2E-14
2E-14
2E-14
2E-14
2E-14
2E-14
1E-15
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
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Parameters
Energy level with respect to Reference (eV)
Table 3 Final Output Parameters 14
HTM/ETM Voc (V) Jsc (mA/cm2) FF (%) PCE (%) 1.155
21.529
87.50
21.76
CuI/CdS
1.231
21.553
82.53
21.90
CuI/ZnSe
1.128
21.554
81.19
19.76
CuI/ZnO
1.155
21.553
87.51
21.79
CuI/ZnOS
1.240
21.524
87.85
23.47
Table 4 Results comparison
Voc (V) Jsc (mA/cm2) FF (%) PCE (%)
HTM/ETM
17.8
62
6
CuI/TiO2[27]
0.78
16.7
57
7.5
CuI/TiO2[9]
1.03
22.78
75
17.6
CuI/TiO2[7]
0.99
25.47
84.53
21.32
CuI/TiO2
1.155
21.529
87.50
21.76
CuI/ZnOS initial
1.240
21.524
87.85
23.47
23.778
87.96
26.11
1.2439
A
CC
EP
TE
D
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CuI/ZnOS optimized
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0.55
N
Simulation
CuI/TiO2[26]
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Experiment
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CuI/TiO2
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S0030-4026(18)31551-1 https://doi.org/10.1016/j.ijleo.2018.10.052 IJLEO 61677
To appear in: Received date: Accepted date:
19-8-2018 8-10-2018
Please cite this article as: Salah MM, Hassan KM, Abouelatta M, Shaker A, A Comparative Study of Different ETMs in Perovskite Solar Cell with Inorganic Copper Iodide as HTM, Optik (2018), https://doi.org/10.1016/j.ijleo.2018.10.052 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
A Comparative Study of Different ETMs in Perovskite
SC RI PT
Solar Cell with Inorganic Copper Iodide as HTM
Mostafa M Salah1, Kamel M. Hassan1, Mohamed Abouelatta2 and Ahmed Shaker2,*
Faculty of Engineering and Technology, Future University, Cairo, Egypt
2
Faculty of Engineering, Ain Shams University, Cairo, Egypt
author. E-mail address: [email protected] (Ahmed Shaker).
M
A
*Corresponding
N
U
1
Abstract
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Perovskite solar cells (PSCs) research is substantially increasing because of the fast
TE
improvement in their power conversion efficiency (PCE), cheapness, possibility to tune the bandgap, low recombination rate, high open circuit voltage, excellent ambipolar charge carrier
EP
transport and strong and broad optical absorption. In this paper, different electron transport
CC
materials (ETMs) have been analyzed with a new Copper Iodide (CuI) Hole Transport Material (HTM) to replace the conventional hole and electron transport materials for PSCs, such as TiO2
A
and Spiro-OMeTAD which have been known to be susceptible to light induced degradation. Moreover, the influence of the ETL, HTL and the perovskite layer thicknesses on the overall cell performance, is studied. The design of the proposed PSC is performed utilizing SCAPS-1D simulator (Solar Cell Capacitance Simulator-one dimension). Because of its high electron affinity and tunable bandgap, ZnOS is found to be the best replacement for TiO2. The results show that 1
lead-based PSC with CuI as HTM is an efficient arrangement and better than the easily degradable and expensive Spiro-OMeTAD. According to the presented simulation and optimization of various
SC RI PT
layers thicknesses, the highest designed efficiency is 26.11%.
Keywords — Perovskite Solar Cell (PSC); Hole transport materials (HTMs); Electron transport materials (ETMs); SCAPS-1D; copper iodide.
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1. Introduction
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Nowadays, Solar is the most natural sources commonly used for renewable energy.
A
Crystalline silicon offers PCEs of up to around 25%; however, the manufacturing of such solar
M
cells is quite costly. For these reasons, new PV technologies based on simple preparation procedures and abundant and cheap materials are required [1]. Lead-based PSCs have gained a
D
significant attention due to their lower cost and simpler fabrication techniques as opposed to
TE
conventional silicon solar cells [2]. PSCs are made from organic-inorganic materials of methyl ammonium lead halides (CH3NH3PbX3, where X = I, Br, or Cl) by different techniques and
EP
structures such as vacuum evaporation and solution schemes, and with planar and mesoporous
CC
heterojunction structures [3]. The PCE of PSCs has improved from 3.8% in 2009 to more than 22% in 2016 [4, 5]. Their success is primarily because of their unique set of electronic properties,
A
such as ambipolar transport properties, micrometer to millimeter charge carrier diffusion lengths, low intrinsic recombination rates, tunable band gaps across the visible region, and large absorption coefficients. In addition to their unique set of electronic properties, low cost techniques for their deposition and synthesis, or alternatively to vapor deposition methods are utilized. These properties make the PSCs one of the best solar cells encountered. 2
CuI shows electrical conductivity two orders higher than Spiro-MeOTAD that allowed higher fill factor (FF) as determined by impedance spectroscopy [6]. Notably, this impressive electrical conductivity is coupled to a low cost, excellent ambient stability, hydrophobic nature,
SC RI PT
wide band gap and solution processability make CuI a very promising HTM material [7]. Initially, PSC with CuI as HTL achieved PCE of 6% [8]. Recently, PCE achieved 17.6% when CuI films were fabricated by facile spray deposition [9]. To study types of these promising cells, simulations are used extensively and one of the most programs used, in this regard, is SCAPS [10]. In this paper, SCAPS is utilized for the simulation of lead-based CH3NH3PbI3 PSCs with
U
CuI as HTM and TiO2, CdS, ZnSe, ZnO, and ZnOS as ETMs to assess promising replacements to
N
TiO2 and Spiro-OMeTAD for CH3NH3PbI3 PSCs. Two interface layers were also used to make
A
the device more practical, each with a thickness of 10 nm. The interface layers were incorporated
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at the HTL/CH3NH3PbX3 interface and at the ETL/CH3NH3PbX3 interface. Furthermore, we
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compared the short circuit current density, open circuit voltage, FF and PCE of the PSCs and
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approved Spiro-MeOTAD and TiO2 be substituted for other materials and that give better performance. The proposed CuI/ZnOS cell grasps the highest PCE of 23.47%. Finally, after
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performing some optimization on the thickness of the absorber layer, HTL, and ETL an efficiency
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of 26.11% is obtained.
2. Modeling and Simulation
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The design of the proposed perovskite p-i-n device structure and the energy band diagram
are illustrated in Figure 1. The proposed structure is comprised of glass substrate / transparent conducting oxide (TCO) / ETL / interface defect layer (IDL) / CH3NH3PbI3 / interface defect layer (IDL) / CuI (HTL) / metal back contact. We have simulated IV n-type materials as ETL for CH3NH3PbI3 PSCs with CuI as HTL. Table 1 indicates the values of the parameters used in the 3
simulation. Table 2 shows the defect properties and their parameters. The flat band model is used for the semiconductor/TCO and semiconductor/metal interfaces. For the parameters not exist in table 1 and 2, the following values were used for all layers: thermal velocity of electrons and holes
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of 107 cm/s [9], neutral defects at the center of the bandgap with a Gaussian distribution, characteristic energy of 0.1 eV, and defect density of 1015 [14]. The absorption coefficient (α) of ETMs, TCO, and CuI was calculated via Equation (1) with the pre-factor (Aα) assumed to be 105 m-1 [11].
(1)
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𝛼(𝐸) = 𝐴𝛼 (ℎν − 𝐸𝑔 )0.5
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Figure 1. Device structure and energy band diagram
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3. Results and Discussion A. CuI as HTM with different ETM Figure 2 shows simulated J-V curves for a CH3NH3PbI3 based device in the n-i-p configuration with CuI as HTL, TiO2, CdS, ZnSe, ZnO, and ZnOS as ETLs. CuI/ZnOS cell has reached the highest PCE of 23.47% with the highest open circuit voltage (Voc) of 1.24 V, current 4
density (Jsc) of 21.524 mA/cm2 and highest FF of 87.85%. CuI/ZnO, CuI/ TiO2 has the same Voc of 1.155 V with very close Jsc of 21.553 mA/cm2, 21.529 mA/cm2, almost same FF of 87.5%, 87.51% and power conversion efficiency of 21.76% and 21.79%, respectively. CuI/CdS cell has
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achieved high PCE of 21.9% with high open circuit voltage (Voc) of 1.231 V, current density (Jsc) of 21.553 mA/cm2 and FF of 82.53%. CuI/ZnSe cell has Voc of 1.128 V with current density (Jsc) of 21.554 mA/cm2 with an efficiency of 19.76% and FF of 81.19%. A comparison of the simulated values of Jsc, Voc, FF, and power conversion efficiency is given in Table 3. Figure 3 shows the quantum efficiency (QE) of the five cells. In SCAPS, QE is the external quantum efficiency (EQE).
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The figure demonstrates that all cells show similar QE curve with minimal differences.
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Fig. 2. J-V curves for CH3NH3PbI3 based solar cells with TiO2, CdS, ZnSe, ZnO, and ZnOS.
5
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Fig. 3. Quantum efficiency curves for CH3NH3PbI3 based solar cells with TiO2, CdS, ZnSe, ZnO,
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A
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and ZnOS.
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B. Influence of thickness of absorber layer
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From the previous section, we get the best performance of CuI/ZnOS cell with PCE of 23.47%. Now we will optimize the thickness of ETM, HTM, and the absorber layer of this cell to
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obtain better performance. H. Anwar [7] has shown an optimum thickness of 600 nm for the absorber layer. We get a PCE of 25.96% which increased by 2.49%, FF of 87.82%, Voc of 1.2439
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V, and Jsc of 23.766 mA/cm2 when we make the thickness of the absorber layer 600 nm.
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C. Influence of thickness of ETM Next, Figure 4 shows the influence of the thickness of ETM on the performance parameters
of the cell when the thickness of the absorber layer is 600 nm. We get the best performance when the thickness of ETM is 30 nm with highest PCE of 25.98% which increased by 0.02%, same FF of 87.82%, same Voc of 1.2439 V, and Jsc of 23.778 mA/cm2. 6
D. Influence of thickness of HTM Moreover, Figure 5 shows the influence of the thickness of HTM on performance parameters of the cell when the thickness of the absorber layer is 600 nm. The performance of the
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cell is inversely proportional to the thickness of HTM. We choose a thickness of 30 nm like the ETM and we get PCE of 26.1% which increased by 0.05%, same FF of 88.29%, same Voc of 1.2439
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V, and Jsc of 23.766 mA/cm2.
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Fig. 4. Variation in performance parameters depending on the variation of the thickness of ETM.
Fig. 5. Variation in performance parameters depending on the variation of the thickness of HTM. 7
Finally, examining the thickness of all layers, we obtained encouraging results, Jsc of 23.778 mA/cm2, Voc of 1.2439 V, FF of 87.96%, and PCE of 26.11%. Figure 6 and Figure 7 indicate the JV and QE respectively of the CuI/ZnOS cell before and after optimization of the
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thickness in the absorber layer, ETM, and HTM. Further, Table 4 displays a comparison between
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our simulated results with the experimental work by the other researchers.
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Fig. 6. J-V curves for CuI/ZnOS cell before and after optimizing the thickness.
Fig. 7. QE curves for CuI/ZnOS cell before and after optimizing the thickness.
8
4. Conclusion Lead-based CH3NH3PbI3 PSC with CuI as HTM and different ETMs are studied by SCAPS simulation. The results show that CuI as alternate HTM has the potential to be used with perovskite
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absorber and can replace the Spiro-MeTAD which is expensive and suffers from degradation. ZnOS is the best ETL material to replace TiO2. The highest PCE achieved is 23.47%. The thickness of the layers has a great influence on the performance parameters of the solar cells. After
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optimizing the thickness of all the layers, we get a PCE of 26.11%.
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5. Acknowledgment
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We would like to express sincere thanks to Dr. Marc Burgelman, Department of Electronics
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and Information Systems (ELIS), University of Gent, Belgium, for providing the SCAPS-1D
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simulation tool.
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References
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[5] Giordano, Fabrizio, Antonio Abate, Juan Pablo Correa Baena, Michael Saliba, Shaik M. Zakeeruddin Shaik M. Zakeeruddin, Sang Hyuk Im, Shaik M. Zakeeruddin, Mohammad Khaja
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improved stability by the introduction of Na-treated TiO2 and spraying-deposited CuI as
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[10] Burgelman, Marc, Koen Decock, Samira Khelifi, and Aimi Abass. "Advanced electrical
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lead based perovskite solar cell using SCAPS-1D." Indian Journal of Science and
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Technology 10, no. 11 (2017).
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[12] Bansal, Shubhra, and Puruswottam Aryal. "Evaluation of new materials for electron and hole transport layers in perovskite-based solar cells through SCAPS-1D simulations."
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In Photovoltaic Specialist Conference (PVSC), 2017 IEEE 44th, pp. 1-4. IEEE, 2017. [13] F. Hao et al., “Anomalous Band Gap Behavior in Mixed Sn and Pb Perovskites Enables
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[14] Samiee, Mehran, Siva Konduri, Balaji Ganapathy, Ranjith Kottokkaran, Hisham A. Abbas, Pranav Joshi, Andrew Kitahara, Liang Zhang, Max Noack, and Vikram Dalal. "Defect density
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and dielectric constant in perovskite solar cells." Applied Physics Letters 105, no. 15 (2014): 153502. [15] Oga, Hikaru, Akinori Saeki, Yuhei Ogomi, Shuzi Hayase, and Shu Seki. "Improved
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[17] Ezealigo, Blessing N., Assumpta C. Nwanya, Aline Simo, Rose U. Osuji, R. Bucher, Malik
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[24] Gloeckler, Markus. "Device physics of Cu (In, Ga) Se2 thin-film solar cells." PhD diss.,
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Colorado State University, 2005.
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Table
Table 1 Simulation Parameters of PSCs Devices IDL
CH3NH3PbI3
CuI
TiO2
Thickness (nm)
500
10
350
100
50
Band gap energy Eg (eV)
3.5
1.55
1.55[12]
2.98[16]
3[20]
Electron affinity χ (eV)
4
3.9
3.9[12]
2.1[17]
4[21]
Relative permittivity ɛr
9
18
18[13]
6.5[18]
9[22]
Effective conduction band density Nc (cm-3)
2.2E+18
2.2E+18
2.2E+18
2.8E+19
2.2E+18
Effective valence band density Nv (cm3)
1.9E+19
1.9E+19
1.9E+19
1E+19
20
3
3[13]
1.69E-4
8
17
17[13]
ZnSe
ZnO
ZnOS
50
50
50
2.4[14]
2.81[12]
3.3[23]
2.83[24]
4.18[14]
4.09[12]
4[23]
3.6[24]
10[14]
8.6[12]
9[23]
9[24]
2.2E+18
2.2E+18
2.2E+18
2.2E+18[24]
1.9E+19
1.9E+19
1.9E+19
1.8E+19[24]
2[20]
100[14]
400[12]
100[23]
100[24]
1.69E-4
1[20]
25[14]
110[12]
25[23]
25[24]
1E+13[15]
0
1E+18
1E+18
1E+18
1E+18
2E+18[24]
0
1E+18[19]
0
0
0
0
0
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50
Hole mobility µp
Donor concentration ND (cm-3)
1E+13
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1E+18
0
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(cm-2 V-1 S-1)
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(cm-2 V-1 S-1)
0
1.9E+19
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Electron mobility µe
Acceptor concentration NA (cm-3)
CdS
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TCO
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Parameters
Table 2 Defect parameters of PSCs Devices TCO
IDL
CH3NH3PbI3
CuI
TiO2
CdS
ZnO
ZnOS
Electrons capture cross section (cm²)
2E-14
2E-14
2E-14
2E-14
2E-14
2E-14
2E-14
1E-15
Holes capture cross section (cm²)
2E-14
2E-14
2E-14
2E-14
2E-14
2E-14
2E-14
1E-15
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
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Parameters
Energy level with respect to Reference (eV)
Table 3 Final Output Parameters 14
HTM/ETM Voc (V) Jsc (mA/cm2) FF (%) PCE (%) 1.155
21.529
87.50
21.76
CuI/CdS
1.231
21.553
82.53
21.90
CuI/ZnSe
1.128
21.554
81.19
19.76
CuI/ZnO
1.155
21.553
87.51
21.79
CuI/ZnOS
1.240
21.524
87.85
23.47
Table 4 Results comparison
Voc (V) Jsc (mA/cm2) FF (%) PCE (%)
HTM/ETM
17.8
62
6
CuI/TiO2[27]
0.78
16.7
57
7.5
CuI/TiO2[9]
1.03
22.78
75
17.6
CuI/TiO2[7]
0.99
25.47
84.53
21.32
CuI/TiO2
1.155
21.529
87.50
21.76
CuI/ZnOS initial
1.240
21.524
87.85
23.47
23.778
87.96
26.11
1.2439
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D
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CuI/ZnOS optimized
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0.55
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Simulation
CuI/TiO2[26]
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Experiment
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CuI/TiO2
15