Journal of Power Sources 450 (2020) 227623
Contents lists available at ScienceDirect
Journal of Power Sources journal homepage: www.elsevier.com/locate/jpowsour
Improving perovskite solar cells photovoltaic performance using tetrabutylammonium salt as additive Shao Jin a, c, Yuelin Wei a, c, **, Bin Rong a, c, Yu Fang a, c, Yuezhu Zhao a, c, Qiyao Guo a, c, Yunfang Huang b, c, *, Leqing Fan a, c, Jihuai Wu a, c a b c
College of Materials Science and Engineering, Huaqiao University, Xiamen, 361021, China College of Chemical Engineering, Huaqiao University, Xiamen, 361021, China Engineering Research Center of Environment-Friendly Functional Materials, Ministry of Education, Huaqiao University, Xiamen, 361021, China
H I G H L I G H T S
G R A P H I C A L A B S T R A C T
� TBAB is employed to improve the qual ity of perovskite films. � The TBAB additive inhibit the carrier recombination and reduce the defect density. � Champion device shows an PCE of 20.16%, increasing by 14.8% over the original one.
A R T I C L E I N F O
A B S T R A C T
Keywords: Perovskites solar cells TBAB Hysteresis effect Power conversion efficiency
At present, the non-radiative recombination loss at the interface is a major challenge for perovskite solar cells (PSCs), which seriously deteriorates the optoelectronic performance of the devices. Here, tetrabutylammonium bromide (TBAB) is incorporated into the perovskite precursor solution utilized as an ion dopant, leading to a high-quality perovskite films with enhanced crystallinity and smooth surface, resulting in decreased grain boundaries and defect density. Thus, the hole-electron recombination and hysteresis effect are effectively sup pressed in the modified devices. Finally, an optimized device yields a maximum power conversion efficiency (PCE) of 20.16%, with an open circuit voltage (VOC) of 1.119 V, a short circuit current density (JSC) of 23.41 mA cm 2, and a fill factor (FF) of 76.97% under 100 mW cm 2 illuminations.
1. Introduction In recent years, perovskite solar cells (PSCs) have been demonstrated to be an ideal photovoltaic device candidate for using solar energy to
overcome the energy crisis [1], due to its simple preparation method [2–4], adjustable band gap [5–7], high carrier mobility [8,9], large absorption coefficient [10,11] and low defect density [12]. During the past few years, the power conversion efficiency (PCE) of PSCs has very
* Corresponding author. Engineering Research Center of Environment-Friendly Functional Materials, Ministry of Education, Huaqiao University, Xiamen 361021, China. ** Corresponding author. Engineering Research Center of Environment-Friendly Functional Materials, Ministry of Education, Huaqiao University, Xiamen 361021, China. E-mail addresses:
[email protected] (Y. Wei),
[email protected] (Y. Huang). https://doi.org/10.1016/j.jpowsour.2019.227623 Received 14 October 2019; Received in revised form 3 December 2019; Accepted 14 December 2019 Available online 20 December 2019 0378-7753/© 2019 Elsevier B.V. All rights reserved.
S. Jin et al.
Journal of Power Sources 450 (2020) 227623
been close to the conventional silicon-based solar cells, (the efficiency of single crystal silicon solar cells is about 25%), which has soared from primary 3.81% in 2009 to amazing certified 23.7% at present [13–17]. It is known that a high-quality perovskite film plays a decisive role in the fabricating of a highly efficient perovskite solar cell [18–21]. The intrinsic interface loss mainly occurs at grain boundaries and interfaces, resulting in the carrier recombination and material degradation. Thus, the non-radiative recombination is enhanced; the carrier lifetime and photoluminescence (PL) yield of perovskite materials are reduced [22–26]. Therefore, numerous efforts have been dedicated to enhancing the PSCs efficiency by controlling the quality of perovskite thin film [27–29]. Lee et al. doped a small amount of phenethylammonium cation into the perovskite layer, resulting in a change in the morphology of the perovskite film, and particularly in the passivation for the grain boundaries [30]. Therefore, the photoluminescence intensity, carrier lifetime of the film, and the open circuit voltage of the device are all increased. Jung et al. have achieved a highly efficient PSCs with stabi lized power conversion efficiency of 20.1% through introducing a long chain molecules of alkylammonium into the MAPbI3 layers, which can be attribute to the restraining non-radiative recombination by the highly preferential orientation [19]. Arivunithi et al. exhibited a PSCs with high efficiency and long-term stability by incorporating a side chain liquid crystal polymer as a dopant into the perovskite film. The increasing grain size in the crystalline perovskite film was controlled by the evaporation of the solvent and the decrease of grain boundaries [31]. Wang et al. demonstrated the formation of a 2D perovskite film at the grain boundaries due to the effectively suppression of non-radiative charge recombination through the addition of n-butylammonium to the FA0.83Cs0.17Pb(IyBr1-y)3 perovskite [32]. Although numerous efforts have been made, the PCE of PSCs are still unsatisfactory for commer cialization application. Thus, suppressing the non-radiative recombi nation loss at the interface is still a big challenging for improving the PCE of PSCs. In this work, tetrabutylammonium bromide (TBAB) is introduced into the perovskite precursor solution used as an ionic additive to obtain a high-quality perovskite film. The origins of the enhancement in PCE are systematically explored using electrochemical and photo luminescence technology. Two-dimension perovskite structure is fabri cated by the TBAB and PbI2 in PSCs, which effectively reduces the PbI2 content and interface defects on the surface of the film. The nonradiative recombination is restrained effectively. The carrier mobility and PL quenching efficiency between the perovskite layer and charge collection layers are enhanced after the addition of appropriate amounts of TBAB. Thus, the PCE of the device exceeding 20% is achieved by the optimized TBAB concentration, which also presented negligible current density–voltage (J–V) hysteresis. Furthermore, these devices modified by appropriate amount of TBAB additive exhibit outstanding reproducibility.
2.2. Device fabrication Fluorine-doped tin oxide (FTO) glass (15 � 15 mm2, 15 Ω/sq) was cleaned in an ultrasonic bath sequentially with detergent, deionized water and ethanol for 20 min. Then, the FTO substrates were treated with UV ozone for 30 min and plasma cleaned for 5 min TiO2 quantum dots (QDs) were spin-coated on above clean FTO substrates by a twostep spin coating method. Afterwards, then FTO substrates covered with TiO2 QDs were heated on a hot plate at 120 � C for 15 min and annealed at 500 � C for 30 min. The layer mesoporous TiO2 precursor solution was prepared by diluting TiO2 paste (30-NRT, Dyesol) in ethanol with a mass ratio of 1: 6. Then, the TiO2 solution was spincoated on the substrate at 4000 rpm for 20 s, and annealed at 500 � C for 30 min to obtain the mesoporous layer. The mixed perovskite precursor solution was prepared by dissolving FAI (1.0 M), PbI2 (1.1 M), MABr (0.2 M) and PbBr2 (0.2 M) in a mixture of anhydrous DMF: DMSO with a volume ratio of (4:1). CsI (5% by volume, 1.5 M DMSO) and varying molar amounts of TBAB were added into the precursor solution to obtain the desired perovskite precursor. The mixed precursor solution was spin-coated onto the compact TiO2 films by a two-step program at 1000 rpm for 10 s and 6000 rpm for 20 s, respectively. During the second step, 120 μL of chlorobenzene was poured at 15 s prior to the end of the program. Then, the substrates were immediately transferred on a hotplate and heated at 100 � C for 60 min. The spiro-OMeTAD solution were prepared by dissolving 70 mg spiroMeOTAD in 1 mL chlorobenzene, as well as an additive of 17.5 μL Libis(trifluoromethanesulfonyl) imide (Li-TFSI) (520 mg of LI-TSFI in 1 mL of acetonitrile) and 28.8 μL 4-tert-butyl pyridine. The hole transport layer (HTL) was deposited by a spin-coating at 1000 rpm and 4000 rpm for 5s and 20 s respectively. The preparation of perovskite absorber and the whole fabrication processes of devices were conducted in a nitrogenfilled glove box. Finally, a gold electrode with a thickness of ~100 nm was thermally evaporated onto the HTL coated film to finish the device fabrication. To test the dark current-voltage curves of perovskite de vices, a PSC device based on PCBM (FTO/TiO2/perovskite/PCBM/Au) was prepared by spin-coating PCBM solution (20 mg mL 1 in chloro benzene) at 1500 rpm for 30 s. 2.3. Characterization The morphology and thickness of the film were observed by a field emission scanning electron microscope (FE-SEM, Hitachi S-8000, Japan). The roughness of the perovskite film surface was measured using an atomic force microscope (AFM) (Intel-ligent mode of the Bruker MM8 instrument). X-ray diffraction (XRD, Bruker AXS, D8 advancement) characterized the crystallinity and crystal structure of the perovskite film with a scan range of 5� –80� and a scan rate of 10� /min. The J-V characteristics were measured using a Keithley 2420 source-measure units under AM 1.5G illumination at 100 mW cm 2 provided by an Oriel Sol 3A solar simulator under ambient conditions. Monochromatic incident photon-to-current conversion efficiency (IPCE) spectra were carried out with the Newport IPCE system (Newport, USA). The ab sorption spectra of the perovskite films were obtained on a Lambda 950 UV/Vis spectrophotometer. Photoluminescence (PL) was used to assess the carrier recombination lifetime. The excitation wavelength was 460 nm. Electrochemical impedance spectroscopy (EIS) testing was con ducted on a CIMPS-4 system (Zahner, ZOYPE) at a 1.0 V bias under AM 1.5G illumination.
2. Experimental 2.1. Materials All the chemicals were used as received without further treatment. Cesium Iodide (CsI), formamidinium iodide (FAI) and methyl ammonium bromide (MABr) were purchased from Xi’an Polymer Light Technology Crop, China. Lead (II) iodide (PbI2, 99.99%), Lead (II) bromide (PbBr2, 99.99%) were purchased from TCI (Shanghai) Devel opment Co., Ltd. Spiro-OMeTAD (99.5%), obtained from Lumtec (Taiwan). Acetonitrile (99.8%), chlorobenzene (CB, 99.8%), Li-bis (tri fluoromethanesulfonyl) imide (Li-TFSI) (99%), TBAB (99.0%), N, NDimethylformamide (DMF, 99.8%) and Dimethyl sulfoxide (DMSO, 99.9%) were purchased from Sigma Aldrich (Korea). Phenyl-C61butyric acid methyl ester (PCBM, 99.5%) obtained from Lumtec Co., Taiwan.
3. Results and discussion The molecular structure diagram of TBAB (C16H36BrN), a kind of semi-clathrate hydrates, is illustrated in Fig. 1a. The stability of the frame structure of perovskite can be improved by the strong interaction between Pb ions with the lone pairs of electrons form N atoms. Mean while, the alkyl chain in TBAB is conductive to achieve smooth 2
S. Jin et al.
Journal of Power Sources 450 (2020) 227623
Fig. 1. (a) Molecular structure of the tetrabutylammonium bromide and (b) architecture of the PSCs.
Fig. 2. (a–e) Top view SEM images of the perovskite film prepared with different concentrations of additive tetrabutylammonium bromide; (f–g) Cross-sectional SEM images of the conventional device and the optimal device (7.5 mm) respectively.
perovskite film, and enhance the crystallinity of the perovskite films with large grain size by delaying the perovskite growth. Furthermore, the free halide ions will release form TBAB during the thermal annealing process, and chelate with the Pb ions during crystal growth to optimize the crystal growth kinetics, thus improve the performance of device [33]. Moreover, the typical planar device scheme of our perovskite de vices doped with TBAB in the light absorption layer is shown in Fig. 1b. The topographic morphological features of the pristine perovskite film and TBAB doped films with different concentrations are investi gated by SEM observation. As shown in Fig. 2, the effect of TBAB with
different concentration (0, 5, 7.5, 10 and 15 mM) plays a major role on the crystallization properties and the microscopic surface texture of the perovskite layer. The origin perovskite film depicts the most particles size about 200–400 nm with a small amount of large particles about 500 nm. In addition, the clear grain boundaries and a few pinholes present in the origin perovskite film. However, even a small number of defects will block the charge transport, result in the recombination of photogenerated carriers, and thus debase the photovoltaic performance of PSCs. When the TBAB is introduced into the perovskite precursor solu tion, the grain size of the perovskite crystal particles markedly increases. 3
S. Jin et al.
Journal of Power Sources 450 (2020) 227623
Fig. 3. (a–e) Atomic force microscopy images of perovskite films modified with different TBAB concentration (0, 5, 7.5, 10 and 15 mM).
Fig. 4. Spectroscopic studies of perovskite films modified with 0, 5, 7.5, 10, and 15 mM of TBAB: (a) XRD patterns; (b) absorption spectra; (c) TRPL spectra; and (d) PL spectra.
A relatively compact, smooth, well-crystallized and uniform grains size (most about 500 nm) of perovskite film without pinholes and excess PbI2 is obtained with 7.5 mM TBAB. The phenomenon can be attribute to the
TBAB additive temporarily chelate with Pbþ2 during the crystal growth, which enhances the homogenous nucleation and alters the interfacial energy, thus modifying the kinetics of crystal growth. The high-quality 4
S. Jin et al.
Journal of Power Sources 450 (2020) 227623
perovskite light absorption layer will beneficial for the enhancement of short-circuit current and fill factor the PSCs, which can be attributed to the larger perovskite grains effectively suppresses charge recombination through their decreased concentration of grain boundaries. Fig. 2f and g presents the cross-sectional SEM image of the pristine perovskite device and the optimized device (7.5 mM TBAB), respectively. The perovskite grains doped with the 7.5 mM TBAB can completely penetrate the entire perovskite light absorber layer, with a denser film and less grain boundaries than that of original perovskite film, which is consistent well with the observation of the top view SEM images. Moreover, AFM is performed to study the effect of TBAB introduction on the morphology of perovskite film. As shown in Fig. 3, the root-meansquare roughness Ra values of the perovskite films produced by various TBAB concentration (0, 5, 7.5, 10 and 15 mM) are approximately 19.8, 16.4, 15.4, 15.8, and 30.0 nm, respectively. Among them, the perovskite film treated with 7.5 mM TBAB obviously presents the lowest surface roughness values, which are coincide with the SEM images. It is believed that a smooth and dense covering layer is very important in achieving high-performance PCSs, which is conducive to reducing grain boundary defect density, decreasing non-radiative recombination of charge, enhancing carrier transport performance and thereby improving overall performance of the device. Fig. 4a shows the XRD spectra of the perovskite films pretreated by TBAB with different concentrations. A pronounced peak at 12.7� is observed in the pristine perovskite layer, indicating the presence of excess PbI2 in the perovskite films. However, the peak of PbI2 disappears after the TBAB introduced into the perovskite layer. Comparing with the original perovskite film, the XRD patterns illustrate the perovskite layer pretreated by TBAB has better crystallinity and bigger grain size by comparing the two characteristic diffraction intensity of (110) and (220) peaks. This indicates that the TBAB additive improves the degree of perovskite crystallinity by altering the crystallization kinetics effec tively. In addition, a new diffraction differential peak is appeared at low angle (2θ ¼ 7.8� ) in the perovskite thin films doped with TBAB, which can be assigned to the (020) crystal plane of 2D perovskite [34]. Furthermore, no other impurity peaks can be found, indicating the phase purity of perovskite crystal. Then, the effect of TBAB on the light absorption of the perovskite film is examined by UV–Vis absorption spectrum. As shown in Fig. 4b, all perovskite films present similar typically characteristic profiles with an onset at 760 nm, which can be attributed to the characteristic band-gap absorption of perovskite works as a light harvester. The multiple slopes are clearly observed in the range of absorption spectra, suggesting the establishment of 2D perovskite film [35]. Apparently, the optical ab sorption intensity of perovskite film doped with TBAB concentration of 5–10 mM is higher than that of the original perovskite film over the entire light absorption region. It will beneficial for increasing the inci dent photon to current conversion efficiency of devices. To illustrate the optoelectronic impact of the TBAB introduced into the perovskite layer, the photoluminescence of the films was investi gated. As presented in Fig. 4c, the time-resolved PL (TRPL) decay of perovskite films modified with different concentrations TBAB can be fitted to a biexponential decay function (Eqn. (1)) [36]. � � � � � t t IðtÞ ¼ Aexp þ B exp (1)
τ1
Table 1 Time-resolved PL fitting parameters of perovskite film with different TBAB concentrations. TBAB (mM)
A1 (%)
τ1/ns
A2 (%)
τ2/ns
Average/ns
0 5 7.5 10 15
60.96 79.74 84.05 83.23 74.15
74.81 78.37 97.34 88.30 66.75
26.77 20.26 15.95 16.77 25.85
7.72 9.30 11.46 11.23 7.30
60.95 64.32 83.64 75.38 51.38
crystallinity in this film. For comparison, the steady state PL spectrum of perovskite films are also investigated with different concentration TBAB modification. As shown in Fig. 4d, the characteristic emission peak of perovskite at around 755 nm is observed. Clearly, the intensity of the PL spectrum of perovskite film enhanced with the increase of the TBAB concentration from 0 to 7.5 mM. However, the intensity of the PL spectrum reduces after further increase the TBAB concentration. The enhancement of PL intensity is most prominent, indicating that the appropriate amount of TBAB can effectively inactivate the defects in the perovskite film, and thus improve the quality of the film. Furthermore, the trap density (nt) is evaluated based on the FTO/ TiO2/perovskite/PCBM/Au device structure using the space charge limited current (SCLC) technique in the dark. As measured in Fig. 5a and b, the VTFL values of the primitive and modified (with 7.5 mM TBAB) perovskite films are 0.79 and 0.54 V, respectively. Then, the nt can be calculated from the trap field limited voltage (VTFL) according to the following equation [37]: nt ¼
2ε0 εVTFL eL2
(2)
where ε0, ε, e and L are the vacuum permittivity, relative dielectric constant, electron charge and the thickness of the as-prepared perovskite films, respectively. Thus, the corresponding trap density values are 1.223 � 1016 cm 3 and 0.836 � 1016 cm 3, respectively. The defect states density of perovskite film modified with TBAB is lower than that of original perovskite film, illustrating that the addition of TBAB can effectively passivate the film, reduce the pore and interface defects of the film, thereby improve the film quality and performance. To further investigate the effective interface for charge transport information, the EIS of the device is carried out at a 1.0 V bias under AM 1.5G illumination. Fig. 5c depicts the Nyquist plot of the reference and TBAB doped devices. There are two distinct semicircles observed upon the reference cell and the devices modified with different concentration TBAB. The first semicircle, at high frequencies region, is related to the charge transport resistance (RCTR) at the interface of perovskite/Au conductive electrode [38,39]. The second semicircle, at low frequencies region, is associated with the charge recombination resistance (RREC) at the TiO2/perovskite interface. The larger radius of the circle signifies the larger the interface resistance, suggesting the harder of electron transfer. The simplified circuit of the equivalent circuit is illustrated in the inset of Fig. 5c. The parameters are calculated using the equivalent circuit model. RS is the series resistance of the device. Usually, the contact resistance of the conductive electrode is constant. Hence, the impedance is primarily determined by the RREC. Notably, the RCTR value for the reference cell (51.8 Ω) is four times higher than that of optimized de vices (12.0 Ω), indicating the interface defect is reduced dramatically, thus resulting in the enhancement of charge extraction from perovskite layer to charge collection layers in the modified devices. Fig. 6a shows the J–V curves for the devices fabricated with different concentrations of TBAB. The corresponding key photovoltaic parame ters are summarized in Table 2. The PCE for original perovskite solar cell is 17.56% with open circuit voltage (VOC) of 1.097 V, a short circuit current density (JSC) of 21.49 mA cm 2, and a fill factor (FF) of 74.47%. Clearly, the performance of the devices is significantly affected by the
τ2
The fast decay process (τ1) is originated from the consequence of the free charge carriers transport from the perovskite layer to the charge collection layers. The slow decay process (τ2) is attributed to the radi ative recombination of the free charge carriers in the perovskite layer. The corresponding lifetimes are summarized in Table 1. More signifi cantly, the longest fast and slow decay lifetimes are appeared upon perovskite film modified by the 7.5 mM TBAB, suggesting that the doping of TBAB reduces the charge trap density and inhibits interfacial carrier recombination effectively due to the fewer defects and higher 5
S. Jin et al.
Journal of Power Sources 450 (2020) 227623
Fig. 5. Dark current-voltage curves of perovskite devices with FTO/TiO2/perovskite/PCBM/Au structure formed at different concentrations of TBAB additives: (a) 0 mM, and (b)7.5 mM as a representative; (c) Nyquist plots of perovskite solar cells.
Fig. 6. (a) Current–voltage characteristics of perovskite solar cells modified with different concentrations of TBAB; (b) Current–voltage characteristics of perovskite solar cells modified with 0 and 7.5 mA TBAB under the reverse and forward scan directions, respectively.
introduction of TBAB amount. When the TBAB concentration is increased to 7.5 mM, dramatically enhanced performance is presented with a the PCE of 20.16%, along with a VOC of 1.119 V, JSC of 23.41 mA cm 2, and an FF of 76.97%. The significant increase in JSC and FF is attributed to the formation of high-quality perovskite grains by doping of TBAB, which effectively suppresses charge recombination. However, the performance of devices decreases with the further increase of TBAB concentration from 7.5 to 15 mM. Fig. 6b shows the J-V curve of the reference and champion cells doped with 7.5 mM TBAB using forward and reverse scan directions to explore the hysteresis behavior. The key parameters are summarized in Table 3. The hysteresis index (HI) is used to quantify the hysteresis loss
Table 2 Key J–V parameters measured for doped with different TBAB concentrations. TBAB (mM)
Voc (V)
Jsc (mA⋅ cm 2)
FF (%)
PCE (%)
0 5 7.5 10 15
1.097 1.114 1.119 1.116 1.096
21.49 22.45 23.41 21.93 21.63
74.47 72.89 76.97 76.49 64.98
17.56 18.24 20.16 18.72 15.42
6
S. Jin et al.
Journal of Power Sources 450 (2020) 227623
(0.071) is much lower than that of the reference device (0.22). It can be attributed to the passivated perovskite layer by the doping of TBAB, resulting in a decrease in trap density in the perovskite layer. In addition to hysteresis, the influence of the TBAB contents on the device’s reproducibility is explored. 20 devices for both reference and champion cells are fabricated under the same condition to verify the repeatability of the device performance. Fig. 7 shows the device statis tics plots and the key parameters of the J-V curve, such as VOC, JSC, FF, and PCE, are statistically distributed. Apparently, all parameters of optimized device are significantly better than those of original device. Outstanding repeatability is stated clearly from the histograms of photovoltaic parameters with small standard deviation. The IPCE spectrum of the devices fabricated by original and cham pion perovskite layers are illustrated in Fig. 8a. All the devices exhibit a strong optical sensitivity spanning from 360 to 750 nm. However, overall IPCE value of optimizes device is higher than that of control
Table 3 Photovoltaic parameters of devices based on original and optimal perovskite layers (forward and backward scanning directions). TBAB (mM)
Scanning mode
Voc (V)
Jsc (mA⋅cm 2)
FF (%)
PCE (%)
0
Reverse Forward Reverse Forward
1.097 1.056 1.119 1.116
21.49 20.26 23.41 21.93
74.47 63.95 76.97 76.49
17.56 13.69 20.16 18.73
7.5
of the devices according to the following equation [31]: HI ¼
PCEreverse PCEforward PCEreverse
(3)
where PCEreverse and PCEforward are power conversion efficiency from reverse and forward scan, respectively. The HI of the champion PSCs
Fig. 7. Photovoltaic parameters of devices based on original and optimal perovskite layers: (a) PCE, (b) VOC, (c) JSC, and (d) FF.
Fig. 8. (a) IPCE spectra and integrated current densities based on the original and best device, respectively; and (b) Steady-state output of the best-performing device under bias of 0.88 V. 7
S. Jin et al.
Journal of Power Sources 450 (2020) 227623
devices, due to its higher absorbance. Furthermore, the maximum IPCE over 90% from 450 nm to 600 nm are clearly observed upon the champion perovskite layers, suggesting a high-quality perovskite film is fabricated for efficient charge transport. The integrated current density of optimal devices estimated from the IPCE spectra is 21.20 mA cm 2, which is higher than that of reference device (19.99 mA cm 2). The result is in consistent well with the UV–vis absorption spectra and Jsc value obtained from the J–V curves. Fig. 8b shows the corresponding steady-state outputs of photocurrent density and PCE output of the de vices base on the best perovskite layers at the maximum power points. For the champion device, a stable PCE of 18.8% can be obtained with a stable photocurrent density of 22.11 mA cm 2. The steady-state photocurrent measured at the maximum power point (0.88 v) is close to the photocurrent measured by the J-V scan (within the margin of error). Long term stability is a critical issue for perovskite devices. The J V curves of the devices fabricated by original and champion perovskite films are measured in a the nitrogen-filled glove box for 30 days. As illustrated in Fig. S1, the normalized parameters of original device including PCE, Jsc, Voc, and FF present continued declines during the aging process. However, the champion device show very small decrease in photovoltaic parameters during the measuring time of 30 days. These results confirm that the TBAB additive improves the stability of devices significantly.
References [1] M.M. Lee, J. Teuscher, T. Miyasaka, T.N. Murakami, H.J. Snaith, Science 338 (2012) 643–647. [2] N.J. Jeon, J.H. Noh, Y.C. Kim, W.S. Yang, S. Ryu, S. II Seok, Nat. Mater. 13 (2014) 897–903. [3] Z.G. Xiao, C. Bi, Y.C. Shao, Q.F. Dong, W. Qi, Y.B. Yuan, C.G. Wang, Y.L. Gao, J. S. Huang, Energy Environ. Sci. 7 (2014) 2619–2623. [4] F.X. Xie, C.C. Chen, Y.Z. Wu, X. Li, M.L. Cai, X. Liu, X.D. Yang, L.Y. Han, Energy Environ. Sci. 10 (2017) 1942–1949. [5] I. Zimmermann, S. Aghazada, M.K. Nazeeruddin, Angew. Chem. Int. Ed. 58 (2019) 1072–1076. [6] Y.N. Zhang, B. Li, L. Fu, Y. Zou, Q. Li, L.W. Yin, Sol. Energy Mater. Sol. Cells 194 (2019) 168–176. [7] D.W. Zhao, C. Chen, C.L. Wang, M.M. Junda, Z.N. Song, C.R. Grice, Y. Yu, C.W. Li, B. Subedi, N.J. Podraza, X.Z. Zhao, G.J. Fang, R.G. Xiong, K. Zhu, Y.F. Yan, Nat. Energy 3 (2018) 1093–1100. [8] S.D. Stranks, G.E. Eperon, G. Grancini, C. Menelaou, M.J.P. Alcocer, T. Leijtens, L. M. Herz, A. Petrozza, H.J. Snaith, Science 342 (2013) 341–344. [9] R.J. Holmes, Enhancing energy transport in conjugated polymers, Science 360 (2018) 854–855. [10] D.P. Mcmeekin, G. Sadoughi, W. Rehman, G.E. Eperon, M. Saliba, M.T. H€ orantner, A. Haghighirad, N. Sakai, L. Korte, B. Rech, M.B. Johnston, L.M. Herz, H.J. Snaith, Science 351 (2016) 151–155. [11] T.W. Ng, H.T. Chandran, C.Y. Chan, M.F. Lo, C.S. Lee, ACS Appl. Mater. Interfaces 7 (2015) 20280–20284. [12] H. Oga, A. Saeki, Y. Ogomi, S. Hayase, S. Seki, J. Am. Chem. Soc. 136 (2014) 13818–13825. [13] A. Kojima, K. Teshima, Y. Shirai, T. Miyasaka, J. Am. Chem. Soc. 131 (2009) 6050–6051. [14] W.Y. Nie, H. Tsai, R. Asadpour, J.C. Blancon, A.J. Neukirch, G. Gupta, J.J. Crochet, M. Chhowalla, S. Tretiak, M.A. Alam, H.L. Wang, A.D. Mohite, Science 347 (2015) 522–525. [15] E.H. Jung, N.J. Jeon, E.Y. Park, C.S. Moon, T.J. Shin, T.Y. Yang, J.H. Noh, J. Seo, Nature 567 (2019) 511–515. [16] Y.S. Sheng, A. Mei, S. Liu, M. Duan, P. Jiang, C.B. Tian, Y.L. Xiong, Y.G. Rong, H. W. Han, Y. Hu, J. Mater. Chem. 6 (2019) 2360–2364. [17] NREL BRCE chart. http://www.nrel.gov/pv/assets/pdfs/pv-efficiency_chart.20181 221.pdf. [18] Q. Jiang, Y. Zhao, X.W. Zhang, X.L. Yang, Y. Chen, Z.M. Chu, Q.F. Ye, X.X. Li, Z. G. Yin, J.B. You, Nat. Photonics 29 (2017), 1606258. [19] M. Jung, T.J. Shin, J. Seo, G. Kim, S. II Seok, Energy Environ. Sci. 11 (2018) 2188–2197. [20] J.F. Lu, X.F. Lin, X.C. Jiao, T. Gengenbach, A.D. Scully, L.C. Jiang, B. Tan, J.S. Sun, B. Li, N. Pai, U. Bach, A.N. Simonov, Y.B. Cheng, Energy Environ. Sci. 11 (2018) 1880–1889. [21] S. II Seok, M. Gr€ atzel, N.G. Park, Small 14 (2018), 1704177. [22] D. Shi, V. Adinolfi, R. Comin, M.J. Yuan, E. Alarousu, A. Buin, Y. Chen, S. Hoogland, A. Rothenberger, K. Katsiev, Y. Losovyj, X. Zhang, P.A. Dowben, O. F. Mohammed, E.H. Sargent, O.M. Bakr, Science 347 (2015) 519–522. [23] Q. Wang, B. Chen, Y. Liu, Y.H. Deng, Y. Bai, Q.F. Dong, J.S. Huang, Energy Environ. Sci. 10 (2017) 516–522. [24] X. Liu, Y.F. Zhang, L. Shi, Z.H. Liu, J.L. Huang, J.S. Yun, Y.Y. Zeng, A. Pu, K. Sun, Z. Hameiri, J.A. Stride, J. Seidel, M.A. Green, X.J. Hao, Adv. Energy Mater. 8 (2018), 1800138. [25] B. Chen, P.N. Rudd, S. Yang, Y.B. Yuan, J.S. Huang, Chem. Soc. Rev. 14 (2019) 3842–3867. [26] F. Ambrosio, J. Wiktor, F. De Angelis, A. Pasquarello, Energy Environ. Sci. 11 (2018) 101–105. [27] H. Chen, F. Ye, W.T. Tang, J.J. He, M.S. Yin, Y.B. Wang, F.X. Xie, E.B. Bi, X.D. Yang, M. Gr€ atzel, L.Y. Han, Nature 550 (2017) 92–95, 550. [28] Y. Zhang, S.G. Kim, D. Lee, H. Shin, N.G. Park, Energy Environ. Sci. 12 (2019) 308–321. [29] J.K. Nam, S.U. Chai, W. Cha, Y.J. Choi, W. Kim, M.S. Jung, J. Kwon, D. Kim, J. H. Park, Nano Lett. 17 (2017) 2028–2033. [30] D.S. Lee, J.S. Yun, J. Kim, A.M. Soufiani, S. Chen, Y. Cho, X. Deng, J. Seidel, S. Lim, S. Huang, A.W.Y. Ho-Baillie, Acs Energy Lett. 3 (2018) 647–654. [31] V.M. Arivunithi, S.S. Reddy, V.G. Sree, H.Y. Park, J. Park, Y.C. Kang, E.S. Shin, Y. Y. Noh, M. Song, S.H. Jin, Adv. Energy Mater. 8 (2018), 1801637. [32] Z.P. Wang, Q.Q. Lin, F.P. Chmiel, N. Sakai, L.M. Herz, H.J. Snaith, Nat. Energy 2 (2017), 17135. [33] T.T. Li, Y.F. Pan, Z. Wang, Y.D. Xia, Y.H. Chen, W. Huang, J. Mater. Chem. 5 (2017) 12602–12652. [34] Y. Wei, H.L. Chu, Y.Y. Tian, B.Q. Chen, K.F. Wu, J.H. Wang, X.C. Yang, B. Cai, Y. F. Zhang, J.J. Zhao, Adv. Energy Mater. 9 (2019), 1900612. [35] W.J. Ke, L.L. Mao, C.C. Stoumpos, J. Hoffman, I. Spanopoulos, A.D. Mohite, M. G. Kanatzidis, Adv. Energy Mater. 9 (2019), 1803384. [36] U.K. Thakur, S. Zeng, P. Kumar, S. Patel, R. Kisslinger, Y. Zhang, P. Kar, A. Goswami, T. Thundat, A. Meldrum, K. Shankar, J. Power Sources 417 (2019) 176–187. [37] Z.H. Liu, J.N. Hu, H.Y. Jiao, L. Li, G.H.J. Zheng, Y.H. Chen, Y. Huang, Q. Zhang, C. Shen, Q. Chen, H.P. Zhou, Adv. Mater. 29 (2017), 1606774. [38] Y.L. Feng, J.M. Bian, S. Wang, C.Y. Zhang, M.H. Wang, Y.T. Shi, J. Mater. Chem. C 7 (2019) 8294–8302. [39] D.L. Shen, W.F. Zhang, F.Y. Xie, Y.F. Li, A. Abate, M.D. Wei, J. Power Sources 402 (2018) 320–326.
4. Conclusions In conclusion, we elaborate a facile approach to fabricate highquality perovskite film with the improved device performance. It has been found that the quality of perovskite crystals is enhanced by the incorporation of TBAB as ionic additive into the perovskite precursor solution, resulting in a low charge recombination rate and defect density within the perovskite films, thus greatly improving the performance of the PSCs device. Compared with the original device, the PCE of cham pion PSCs increases significantly from 17.56% to a maximum of 20.16%, along with a VOC of 1.119 V, JSC of 23.41 mA cm 2, and an FF of 76.97%. Moreover, the hysteresis effect of the modified device is greatly reduced. Declaration of competing interestCOI There are no conflicts to declare. We fully abide the ethical re quirements of Journal of Power Sources. The work described in this manuscript has not been published previously and is not under consid eration for publication elsewhere. This publication is approved by all authors. If the article accepted, it will not be published elsewhere in the same form, in English or in any other language, without the written consent of the Publisher. Acknowledgements This work is supported by the National Natural Science Foundation of China (No. 61306077, U1705256), the Fundamental Research Funds for the Central Universities (JB-ZR1109, JB-ZR1212), Promotion Pro gram for Young and Middle-aged Teacher in Science and Technology Research of Huaqiao University (ZQN-PY207), Subsidized Project for Postgraduates’ Innovative Fund in Scientific Research of Huaqiao Uni versity (No. 18013081026), the Open Project Program of Provincial Key Laboratory of Eco-Industrial Green Technology of Wuyi University. Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi. org/10.1016/j.jpowsour.2019.227623.
8