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1.
Reduced Interface‐Mediated Recombination for High Open‐Circuit Voltages in CH3NH3PbI3 Solar Cells
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Christian M. Wolff Fengshuo Zu Andreas Paulke Lorena Perdigón Toro Norbert Koch Dieter Neher 《Advanced materials (Deerfield Beach, Fla.)》2017,29(28)
Perovskite solar cells with all‐organic transport layers exhibit efficiencies rivaling their counterparts that employ inorganic transport layers, while avoiding high‐temperature processing. Herein, it is investigated how the choice of the fullerene derivative employed in the electron‐transporting layer of inverted perovskite cells affects the open‐circuit voltage (VOC). It is shown that nonradiative recombination mediated by the electron‐transporting layer is the limiting factor for the VOC in the cells. By inserting an ultrathin layer of an insulating polymer between the active CH3NH3PbI3 perovskite and the fullerene, an external radiative efficiency of up to 0.3%, a VOC as high as 1.16 V, and a power conversion efficiency of 19.4% are realized. The results show that the reduction of nonradiative recombination due to charge‐blocking at the perovskite/organic interface is more important than proper level alignment in the search for ideal selective contacts toward high VOC and efficiency. 相似文献
2.
Interfacial Passivation of the p‐Doped Hole‐Transporting Layer Using General Insulating Polymers for High‐Performance Inverted Perovskite Solar Cells
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Fan Zhang Jun Song Rui Hu Yuren Xiang Junjie He Yuying Hao Jiarong Lian Bin Zhang Pengju Zeng Junle Qu 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(19)
Organic–inorganic lead halide perovskite solar cells (PVSCs), as a competing technology with traditional inorganic solar cells, have now realized a high power conversion efficiency (PCE) of 22.1%. In PVSCs, interfacial carrier recombination is one of the dominant energy‐loss mechanisms, which also results in the simultaneous loss of potential efficiency. In this work, for planar inverted PVSCs, the carrier recombination is dominated by the dopant concentration in the p‐doped hole transport layers (HTLs), since the F4‐TCNQ dopant induces more charge traps and electronic transmission channels, thus leading to a decrease in open‐circuit voltages (VOC). This issue is efficiently overcome by inserting a thin insulating polymer layer (poly(methyl methacrylate) or polystyrene) as a passivation layer with an appropriate thickness, which allows for increases in the VOC without significantly sacrificing the fill factor. It is believed that the passivation layer attributes to the passivation of interfacial recombination and the suppression of current leakage at the perovskite/HTL interface. By manipulating this interfacial passivation technique, a high PCE of 20.3% is achieved without hysteresis. Consequently, this versatile interfacial passivation methodology is highly useful for further improving the performance of planar inverted PVSCs. 相似文献
3.
Shanshan Zhang Seyed M. Hosseini Ren Gunder Andrei Petsiuk Pietro Caprioglio Christian M. Wolff Safa Shoaee Paul Meredith Susan Schorr Thomas Unold Paul L. Burn Dieter Neher Martin Stolterfoht 《Advanced materials (Deerfield Beach, Fla.)》2019,31(30)
2D Ruddlesden–Popper perovskite (RPP) solar cells have excellent environmental stability. However, the power conversion efficiency (PCE) of RPP cells remains inferior to 3D perovskite‐based cells. Herein, 2D (CH3(CH2)3NH3)2(CH3NH3)n?1PbnI3n+1 perovskite cells with different numbers of [PbI6]4? sheets (n = 2–4) are analyzed. Photoluminescence quantum yield (PLQY) measurements show that nonradiative open‐circuit voltage (VOC) losses outweigh radiative losses in materials with n > 2. The n = 3 and n = 4 films exhibit a higher PLQY than the standard 3D methylammonium lead iodide perovskite although this is accompanied by increased interfacial recombination at the top perovskite/C60 interface. This tradeoff results in a similar PLQY in all devices, including the n = 2 system where the perovskite bulk dominates the recombination properties of the cell. In most cases the quasi‐Fermi level splitting matches the device VOC within 20 meV, which indicates minimal recombination losses at the metal contacts. The results show that poor charge transport rather than exciton dissociation is the primary reason for the reduction in fill factor of the RPP devices. Optimized n = 4 RPP solar cells had PCEs of 13% with significant potential for further improvements. 相似文献
4.
Yuze Lin Bo Chen Fuwen Zhao Xiaopeng Zheng Yehao Deng Yuchuan Shao Yanjun Fang Yang Bai Chunru Wang Jinsong Huang 《Advanced materials (Deerfield Beach, Fla.)》2017,29(26)
Efficient wide‐bandgap (WBG) perovskite solar cells are needed to boost the efficiency of silicon solar cells to beyond Schottky–Queisser limit, but they suffer from a larger open circuit voltage (VOC) deficit than narrower bandgap ones. Here, it is shown that one major limitation of VOC in WBG perovskite solar cells comes from the nonmatched energy levels of charge transport layers. Indene‐C60 bisadduct (ICBA) with higher‐lying lowest‐unoccupied‐molecular‐orbital is needed for WBG perovskite solar cells, while its energy‐disorder needs to be minimized before a larger VOC can be observed. A simple method is applied to reduce the energy disorder by isolating isomer ICBA‐tran3 from the as‐synthesized ICBA‐mixture. WBG perovskite solar cells with ICBA‐tran3 show enhanced VOC by 60 mV, reduced VOC deficit of 0.5 V, and then a record stabilized power conversion efficiency of 18.5%. This work points out the importance of matching the charge transport layers in perovskite solar cells when the perovskites have a different composition and energy levels. 相似文献
5.
Cong‐Cong Zhang Zhao‐Kui Wang Shuai Yuan Rui Wang Meng Li Musibau Francis Jimoh Liang‐Sheng Liao Yang Yang 《Advanced materials (Deerfield Beach, Fla.)》2019,31(30)
In hybrid organic–inorganic lead halide perovskite solar cells, the energy loss is strongly associated with nonradiative recombination in the perovskite layer and at the cell interfaces. Here, a simple but effective strategy is developed to improve the cell performance of perovskite solar cells via the combination of internal doping by a ferroelectric polymer and external control by an electric field. A group of polarized ferroelectric (PFE) polymers are doped into the methylammonium lead iodide (MAPbI3) layer and/or inserted between the perovskite and the hole‐transporting layers to enhance the build‐in field (BIF), improve the crystallization of MAPbI3, and regulate the nonradiative recombination in perovskite solar cells. The PFE polymer‐doped MAPbI3 shows an orderly arrangement of MA+ cations, resulting in a preferred growth orientation of polycrystalline perovskite films with reduced trap states. In addition, the BIF is enhanced by the widened depletion region in the device. As an interfacial dipole layer, the PFE polymer plays a critical role in increasing the BIF. This combined effect leads to a substantial reduction in voltage loss of 0.14 V due to the efficient suppression of nonradiative recombination. Consequently, the resulting perovskite solar cells present a power conversion efficiency of 21.38% with a high open‐circuit voltage of 1.14 V. 相似文献
6.
Highly Efficient Perovskite–Perovskite Tandem Solar Cells Reaching 80% of the Theoretical Limit in Photovoltage
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Adharsh Rajagopal Zhibin Yang Sae Byeok Jo Ian L. Braly Po‐Wei Liang Hugh W. Hillhouse Alex K.‐Y. Jen 《Advanced materials (Deerfield Beach, Fla.)》2017,29(34)
Organic–inorganic hybrid perovskite multijunction solar cells have immense potential to realize power conversion efficiencies (PCEs) beyond the Shockley–Queisser limit of single‐junction solar cells; however, they are limited by large nonideal photovoltage loss (V oc,loss) in small‐ and large‐bandgap subcells. Here, an integrated approach is utilized to improve the V oc of subcells with optimized bandgaps and fabricate perovskite–perovskite tandem solar cells with small V oc,loss. A fullerene variant, Indene‐C60 bis‐adduct, is used to achieve optimized interfacial contact in a small‐bandgap (≈1.2 eV) subcell, which facilitates higher quasi‐Fermi level splitting, reduces nonradiative recombination, alleviates hysteresis instabilities, and improves V oc to 0.84 V. Compositional engineering of large‐bandgap (≈1.8 eV) perovskite is employed to realize a subcell with a transparent top electrode and photostabilized V oc of 1.22 V. The resultant monolithic perovskite–perovskite tandem solar cell shows a high V oc of 1.98 V (approaching 80% of the theoretical limit) and a stabilized PCE of 18.5%. The significantly minimized nonideal V oc,loss is better than state‐of‐the‐art silicon–perovskite tandem solar cells, which highlights the prospects of using perovskite–perovskite tandems for solar‐energy generation. It also unlocks opportunities for solar water splitting using hybrid perovskites with solar‐to‐hydrogen efficiencies beyond 15%. 相似文献
7.
Xinpeng Zhang Xiangyu Li Lei Tao Zemin Zhang Hao Ling Xue Fu Shibo Wang Min Jae Ko Jingshan Luo Jiangzhao Chen Yuelong Li 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(22):2208289
Wide-bandgap perovskite solar cells (PSCs) have attracted a lot of attention due to their application in tandem solar cells. However, the open-circuit voltage (VOC) of wide-bandgap PSCs is dramatically limited by high defect density existing at the interface and bulk of the perovskite film. Here, an anti-solvent optimized adduct to control perovskite crystallization strategy that reduces nonradiative recombination and minimizes VOC deficit is proposed. Specifically, an organic solvent with similar dipole moment, isopropanol (IPA) is added into ethyl acetate (EA) anti-solvent, which is beneficial to form PbI2 adducts with better crystalline orientation and direct formation of α-phase perovskite. As a result, EA-IPA (7-1) based 1.67 eV PSCs deliver a power conversion efficiency of 20.06% and a VOC of 1.255 V, which is one of the remarkable values for wide-bandgap around 1.67 eV. The findings provide an effective strategy for controlling crystallization to reduce defect density in PSCs. 相似文献
8.
Li Chen Jingde Chen Chenyue Wang Hao Ren Hong-Yi Hou Ye-Fan Zhang Yan-Qing Li Xingyu Gao Jian-Xin Tang 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(24):2207817
Both the uncoordinated Pb2+ and excess PbI2 in perovskite film will create defects and perturb carrier collection, thus leading to the open-circuit voltage (VOC) loss and inducing rapid performance degradation of perovskite solar cells (PSCs). Herein, an additive of 3-aminothiophene-2-carboxamide (3-AzTca) that contains amide and amino and features a large molecular size is introduced to improve the quality of perovskite film. The interplay of size effect and adequate bonding strength between 3-AzTca and uncoordinated Pb2+ regulates the mineralization of PbI2 and generates low-dimensional PbI2 phase, thereby boosting the crystallization of perovskite. The decreased defect states result in suppressed nonradiative recombination and reduced VOC loss. The power conversion efficiency (PCE) of modified PSC is improved to 22.79% with a high VOC of 1.22 V. Moreover, the decomposition of PbI2 and perovskite films is also retarded, yielding enhanced device stability. This study provides an effective method to minimize the concentration of uncoordinated Pb2+ and improve the PCE and stability of PSCs. 相似文献
9.
Polymer‐Passivated Inorganic Cesium Lead Mixed‐Halide Perovskites for Stable and Efficient Solar Cells with High Open‐Circuit Voltage over 1.3 V
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Qingsen Zeng Xiaoyu Zhang Xiaolei Feng Siyu Lu Zhaolai Chen Xue Yong Simon A. T. Redfern Haotong Wei Haiyu Wang Huaizhong Shen Wei Zhang Weitao Zheng Hao Zhang John S. Tse Bai Yang 《Advanced materials (Deerfield Beach, Fla.)》2018,30(9)
Cesium‐based trihalide perovskites have been demonstrated as promising light absorbers for photovoltaic applications due to their superb composition stability. However, the large energy losses (Eloss) observed in inorganic perovskite solar cells has become a major hindrance impairing the ultimate efficiency. Here, an effective and reproducible method of modifying the interface between a CsPbI2Br absorber and polythiophene hole‐acceptor to minimize the Eloss is reported. It is demonstrated that polythiophene, deposited on the top of CsPbI2Br, can significantly reduce electron‐hole recombination within the perovskite, which is due to the electronic passivation of surface defect states. In addition, the interfacial properties are improved by a simple annealing process, leading to significantly reduced energy disorder in polythiophene and enhanced hole‐injection into the hole‐acceptor. Consequently, one of the highest power conversion efficiency (PCE) of 12.02% from a reverse scan in inorganic mixed‐halide perovskite solar cells is obtained. Modifying the perovskite films with annealing polythiophene enables an open‐circuit voltage (VOC) of up to 1.32 V and Eloss of down to 0.5 eV, which both are the optimal values reported among cesium‐lead mixed‐halide perovskite solar cells to date. This method provides a new route to further improve the efficiency of perovskite solar cells by minimizing the Eloss. 相似文献
10.
Trap‐State Suppression and Improved Charge Transport in PbS Quantum Dot Solar Cells with Synergistic Mixed‐Ligand Treatments
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Santanu Pradhan Alexandros Stavrinadis Shuchi Gupta Yu Bi Francesco Di Stasio Gerasimos Konstantatos 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(21)
The power conversion efficiency of colloidal PbS‐quantum‐dot (QD)‐based solar cells is significantly hampered by lower‐than‐expected open circuit voltage (VOC). The VOC deficit is considerably higher in QD‐based solar cells compared to other types of existing solar cells due to in‐gap trap‐induced bulk recombination of photogenerated carriers. Here, this study reports a ligand exchange procedure based on a mixture of zinc iodide and 3‐mercaptopropyonic acid to reduce the VOC deficit without compromising the high current density. This layer‐by‐layer solid state ligand exchange treatment enhances the photovoltaic performance from 6.62 to 9.92% with a significant improvement in VOC from 0.58 to 0.66 V. This study further employs optoelectronic characterization, X‐ray photoelectron spectroscopy, and photoluminescence spectroscopy to understand the origin of VOC improvement. The mixed‐ligand treatment reduces the sub‐bandgap traps and significantly reduces bulk recombination in the devices. 相似文献
11.
Pengyang Wang Renjie Li Bingbing Chen Fuhua Hou Jie Zhang Ying Zhao Xiaodan Zhang 《Advanced materials (Deerfield Beach, Fla.)》2020,32(6):1905766
An electron-transport layer (ETL) with appropriate energy alignment and enhanced charge transfer is critical for perovskite solar cells (PSCs). However, interfacial energy level mismatch limits the electrical performance of PSCs, particularly the open-circuit voltage (VOC). Herein, a simple low-temperature-processed In2O3/SnO2 bilayer ETL is developed and used for fabricating a new PSC device. The presence of In2O3 results in uniform, compact, and low-trap-density perovskite films. Moreover, the conduction band of In2O3 is shallower than that of Sn-doped In2O3 (ITO), enhancing the charge transfer from perovskite to ETL, thus minimizing VOC loss at the perovskite and ETL interface. A planar PSC with a power conversion efficiency of 23.24% (certified efficiency of 22.54%) is obtained. A high VOC of 1.17 V is achieved with the potential loss at only 0.36 V. In contrast, devices based on single SnO2 layers achieve 21.42% efficiency with a VOC of 1.13 V. In addition, the new device maintains 97.5% initial efficiency after 80 d in N2 without encapsulation and retains 91% of its initial efficiency after 180 h under 1 sun continuous illumination. The results demonstrate and pave the way for the development of efficient photovoltaic devices. 相似文献
12.
Yu Luo Shuyi Liu Nilesh Barange Li Wang Franky So 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(46):6346-6352
Organometallic halide perovskites solar cells are fabricated on nano‐scaled corrugated substrates using a sequential deposition method. The corrugated substrates are fabricated using colloidal lithography followed by reactive ion etching. The corrugated structure is found to accelerate the chemical reaction between the sequentially deposited lead iodide (PbI2) and methyl ammonium iodide layers to form stoichiometric perovskite films, and the corrugated morphology is preserved at the interface of the hole transport layer (HTL) and the perovskite layer. The shunt resistance of the corrugated devices is found to be higher than that of the planar devices, leading to a higher open circuit voltage (VOC) and fill factor (FF) in the corrugated devices. Finite‐difference time‐domain simulation is carried out on both planar and corrugated devices. The results revealed that light absorption is enhanced in the corrugated devices due to the corrugated HTL/perovskite interface, resulting in a significantly higher short circuit current (JSC) observed in the corrugated devices. As a result, the average power conversion efficiency increases from 8.7% for the planar devices to 13% for the corrugated devices. 相似文献
13.
Ding Zheng Ruixiang Peng Gang Wang Jenna Leigh Logsdon Binghao Wang Xiaobing Hu Yao Chen Vinayak P. Dravid Michael R. Wasielewski Junsheng Yu Wei Huang Ziyi Ge Tobin J. Marks Antonio Facchetti 《Advanced materials (Deerfield Beach, Fla.)》2019,31(40)
Recent perovskite solar cell (PSC) advances have pursued strategies for reducing interfacial energetic mismatches to mitigate energy losses, as well as to minimize interfacial and bulk defects and ion vacancies to maximize charge transfer. Here nonconjugated multi‐zwitterionic small‐molecule electrolytes (NSEs) are introduced, which act not only as charge‐extracting layers for barrier‐free charge collection at planar triple cation PSC cathodes but also passivate charged defects at the perovskite bulk/interface via a spontaneous bottom‐up passivation effect. Implementing these synergistic properties affords NSE‐based planar PSCs that deliver a remarkable power conversion efficiency of 21.18% with a maximum VOC = 1.19 V, in combination with suppressed hysteresis and enhanced environmental, thermal, and light‐soaking stability. Thus, this work demonstrates that the bottom‐up, simultaneous interfacial and bulk trap passivation using NSE modifiers is a promising strategy to overcome outstanding issues impeding further PSC advances. 相似文献
14.
Furui Tan Hairen Tan Makhsud I. Saidaminov Mingyang Wei Mengxia Liu Anyi Mei Peicheng Li Bowen Zhang Chih‐Shan Tan Xiwen Gong Yongbiao Zhao Ahmad R. Kirmani Ziru Huang James Z. Fan Rafael Quintero‐Bermudez Junghwan Kim Yicheng Zhao Oleksandr Voznyy Yueyue Gao Feng Zhang Lee J. Richter Zheng‐Hong Lu Weifeng Zhang Edward H. Sargent 《Advanced materials (Deerfield Beach, Fla.)》2019,31(14)
Organic–inorganic hybrid perovskite solar cells (PSCs) have seen a rapid rise in power conversion efficiencies in recent years; however, they still suffer from interfacial recombination and charge extraction losses at interfaces between the perovskite absorber and the charge–transport layers. Here, in situ back‐contact passivation (BCP) that reduces interfacial and extraction losses between the perovskite absorber and the hole transport layer (HTL) is reported. A thin layer of nondoped semiconducting polymer at the perovskite/HTL interface is introduced and it is shown that the use of the semiconductor polymer permits—in contrast with previously studied insulator‐based passivants—the use of a relatively thick passivating layer. It is shown that a flat‐band alignment between the perovskite and polymer passivation layers achieves a high photovoltage and fill factor: the resultant BCP enables a photovoltage of 1.15 V and a fill factor of 83% in 1.53 eV bandgap PSCs, leading to an efficiency of 21.6% in planar solar cells. 相似文献
15.
P. W. M. Blom V. D. Mihailetchi L. J. A. Koster D. E. Markov 《Advanced materials (Deerfield Beach, Fla.)》2007,19(12):1551-1566
Plastic solar cells bear the potential for large‐scale power generation based on materials that provide the possibility of flexible, lightweight, inexpensive, efficient solar cells. Since the discovery of the photoinduced electron transfer from a conjugated polymer to fullerene molecules, followed by the introduction of the bulk heterojunction (BHJ) concept, this material combination has been extensively studied in organic solar cells, leading to several breakthroughs in efficiency, with a power conversion efficiency approaching 5 %. This article reviews the processes and limitations that govern device operation of polymer:fullerene BHJ solar cells, with respect to the charge‐carrier transport and photogeneration mechanism. The transport of electrons/holes in the blend is a crucial parameter and must be controlled (e.g., by controlling the nanoscale morphology) and enhanced in order to allow fabrication of thicker films to maximize the absorption, without significant recombination losses. Concomitantly, a balanced transport of electrons and holes in the blend is needed to suppress the build‐up of the space–charge that will significantly reduce the power conversion efficiency. Dissociation of electron–hole pairs at the donor/acceptor interface is an important process that limits the charge generation efficiency under normal operation condition. Based on these findings, there is a compromise between charge generation (light absorption) and open‐circuit voltage (VOC) when attempting to reduce the bandgap of the polymer (or fullerene). Therefore, an increase in VOC of polymer:fullerene cells, for example by raising the lowest unoccupied molecular orbital level of the fullerene, will benefit cell performance as both fill factor and short‐circuit current increase simultaneously. 相似文献
16.
Yifan Wang Boyu Jia Jing Wang Peiyao Xue Yiqun Xiao Tengfei Li Jiayu Wang Heng Lu Zheng Tang Xinhui Lu Fei Huang Xiaowei Zhan 《Advanced materials (Deerfield Beach, Fla.)》2020,32(29):2002066
To take advantages of the intense absorption and fluorescence, high charge mobility, and high dielectric constant of CsPbI3 perovskite quantum dots (PQDs), PQD hybrid nonfullerene organic solar cells (OSCs) are fabricated. Addition of PQDs leads to simultaneous enhancement of open-circuit voltage (VOC), short-circuit current density (JSC), and fill factor (FF); power conversion efficiencies are boosted from 11.6% to 13.2% for PTB7-Th:FOIC blend and from 15.4% to 16.6% for PM6:Y6 blend. Incorporation of PQDs dramatically increases the energy of the charge transfer state, resulting in near-zero driving force and improved VOC. Interestingly, at near-zero driving force, the PQD hybrid OSCs show more efficient charge generation than the control device without PQDs, contributing to enhanced JSC, due to the formation of cascade band structure and increased molecular ordering. The strong fluorescence of the PQDs enhances the external quantum efficiency of the electroluminescence of the active layer, which can reduce nonradiative recombination voltage loss. The high dielectric constant of the PQDs screens the Coulombic interactions and reduces charge recombination, which is beneficial for increased FF. This work may open up wide applicability of perovskite quantum dots and an avenue toward high-performance nonfullerene solar cells. 相似文献
17.
Hao Lu Wei Tian Bangkai Gu Yayun Zhu Liang Li 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(38)
In planar perovskite solar cells, it is vital to engineer the extraction and recombination of electron–hole pairs at the electron transport layer/perovskite interface for obtaining high performance. This study reports a novel titanium oxide (TiO2) bilayer with different Fermi energy levels by combing atomic layer deposition and spin‐coating technique. Energy band alignments of TiO2 bilayer can be modulated by controlling the deposition order of layers. The TiO2 bilayer based perovskite solar cells are highly efficient in carrier extraction, recombination suppression, and defect passivation, and thus demonstrate champion efficiencies up to 16.5%, presenting almost 50% enhancement compared to the TiO2 single layer based counterparts. The results suggest that the bilayer with type II band alignment as electron transport layers provides an efficient approach for constructing high‐performance planar perovskite solar cells. 相似文献
18.
Highly Efficient Porphyrin‐Based OPV/Perovskite Hybrid Solar Cells with Extended Photoresponse and High Fill Factor
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Ke Gao Zonglong Zhu Bo Xu Sae Byeok Jo Yuanyuan Kan Xiaobin Peng Alex K.‐Y. Jen 《Advanced materials (Deerfield Beach, Fla.)》2017,29(47)
Employing a layer of bulk‐heterojunction (BHJ) organic semiconductors on top of perovskite to further extend its photoresponse is considered as a simple and promising way to enhance the efficiency of perovskite‐based solar cells, instead of using tandem devices or near infrared (NIR)‐absorbing Sn‐containing perovskites. However, the progress made from this approach is quite limited because very few such hybrid solar cells can simultaneously show high short‐circuit current (JSC) and fill factor (FF). To find an appropriate NIR‐absorbing BHJ is essential for highly efficient, organic, photovoltaics (OPV)/perovskite hybrid solar cells. The materials involved in the BHJ layer not only need to have broad photoresponse to increase JSC, but also possess suitable energy levels and high mobility to afford high VOC and FF. In this work, a new porphyrin is synthesized and blended with [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) to function as an efficient BHJ for OPV/perovskite hybrid solar cells. The extended photoresponse, well‐matched energy levels, and high hole mobility from optimized BHJ morphology afford a very high power conversion efficiency (PCE) (19.02%) with high Voc, JSC, and FF achieved simultaneously. This is the highest value reported so far for such hybrid devices, which demonstrates the feasibility of further improving the efficiency of perovskite devices. 相似文献
19.
Organic–inorganic hybrid perovskite materials are receiving increasing attention and becoming star materials on account of their unique and intriguing optical and electrical properties, such as high molar extinction coefficient, wide absorption spectrum, low excitonic binding energy, ambipolar carrier transport property, long carrier diffusion length, and high defects tolerance. Although a high power conversion efficiency (PCE) of up to 22.7% is certified for perovskite solar cells (PSCs), it is still far from the theoretical Shockley–Queisser limit efficiency (30.5%). Obviously, trap‐assisted nonradiative (also called Shockley–Read–Hall, SRH) recombination in perovskite films and interface recombination should be mainly responsible for the above efficiency distance. Here, recent research advancements in suppressing bulk SRH recombination and interface recombination are systematically investigated. For reducing SRH recombination in the films, engineering perovskite composition, additives, dimensionality, grain orientation, nonstoichiometric approach, precursor solution, and post‐treatment are explored. The focus herein is on the recombination at perovskite/electron‐transporting material and perovskite/hole‐transporting material interfaces in normal or inverted PSCs. Strategies for suppressing bulk and interface recombination are described. Additionally, the effect of trap‐assisted nonradiative recombination on hysteresis and stability of PSCs is discussed. Finally, possible solutions and reasonable prospects for suppressing recombination losses are presented. 相似文献
20.
Qi Jiang Zhenyi Ni Guiying Xu Yun Lin Peter N. Rudd Rongming Xue Yaowen Li Yongfang Li Yongli Gao Jinsong Huang 《Advanced materials (Deerfield Beach, Fla.)》2020,32(31):2001581
Tailoring the doping of semiconductors in heterojunction solar cells shows tremendous success in enhancing the performance of many types of inorganic solar cells, while it is found challenging in perovskite solar cells because of the difficulty in doping perovskites in a controllable way. Here, a small molecule of 4,4′,4″,4″′-(pyrazine-2,3,5,6-tetrayl) tetrakis (N,N-bis(4-methoxyphenyl) aniline) (PT-TPA) which can effectively p-dope the surface of FAxMA1−xPbI3 (FA: HC(NH2)2; MA: CH3NH3) perovskite films is reported. The intermolecular charge transfer property of PT-TPA forms a stabilized resonance structure to accept electrons from perovskites. The doping effect increases perovskite dark conductivity and carrier concentration by up to 4737 times. Computation shows that electrons in the first two layers of octahedral cages in perovskites are transferred to PT-TPA. After applying PT-TPA into perovskite solar cells, the doping-induced band bending in perovskite effectively facilitates hole extraction to hole transport layer and expels electrons toward cathode side, which reduces the charge recombination there. The optimized devices demonstrate an increased photovoltage from 1.12 to 1.17 V and an efficiency of 23.4% from photocurrent scanning with a stabilized efficiency of 22.9%. The findings demonstrate that molecular doping is an effective route to control the interfacial charge recombination in perovskite solar cells which is in complimentary to broadly applied defect passivation techniques. 相似文献