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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.
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
3.
Jishan Shi Yerun Gao Xiang Gao Yun Zhang Junjie Zhang Xin Jing Ming Shao 《Advanced materials (Deerfield Beach, Fla.)》2019,31(37)
Low‐dimensional Ruddlesden–Popper perovskites (RPPs) exhibit excellent stability in comparison with 3D perovskites; however, the relatively low power conversion efficiency (PCE) limits their future application. In this work, a new fluorine‐substituted phenylethlammonium (PEA) cation is developed as a spacer to fabricate quasi‐2D (4FPEA)2(MA)4Pb5I16 (n = 5) perovskite solar cells. The champion device exhibits a remarkable PCE of 17.3% with a Jsc of 19.00 mA cm?2, a Voc of 1.16 V, and a fill factor (FF) of 79%, which are among the best results for low‐dimensional RPP solar cells (n ≤ 5). The enhanced device performance can be attributed as follows: first, the strong dipole field induced by the 4‐fluoro‐phenethylammonium (4FPEA) organic spacer facilitates charge dissociation. Second, fluorinated RPP crystals preferentially grow along the vertical direction, and form a phase distribution with the increasing n number from bottom to the top surface, resulting in efficient charge transport. Third, 4FPEA‐based RPP films exhibit higher film crystallinity, enlarged grain size, and reduced trap‐state density. Lastly, the unsealed fluorinated RPP devices demonstrate superior humidity and thermal stability. Therefore, the fluorination of the long‐chain organic cations provides a feasible approach for simultaneously improving the efficiency and stability of low‐dimensional RPP solar cells. 相似文献
4.
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
5.
Shuai Yuan Zhao‐Kui Wang Lei‐Xin Xiao Chun‐Feng Zhang Sheng‐Yi Yang Bing‐Bing Chen Hui‐Ting Ge Qi‐Sheng Tian Yan Jin Liang‐Sheng Liao 《Advanced materials (Deerfield Beach, Fla.)》2019,31(44)
Compared to efficient green and near‐infrared light‐emitting diodes (LEDs), less progress has been made on deep‐blue perovskite LEDs. They suffer from inefficient domain [various number of PbX6? layers (n)] control, resulting in a series of unfavorable issues such as unstable color, multipeak profile, and poor fluorescence yield. Here, a strategy involving a delicate spacer modulation for quasi‐2D perovskite films via an introduction of aromatic polyamine molecules into the perovskite precursor is reported. With low‐dimensional component engineering, the n1 domain, which shows nonradiative recombination and retarded exciton transfer, is significantly suppressed. Also, the n3 domain, which represents the population of emission species, is remarkably increased. The optimized quasi‐2D perovskite film presents blue emission from the n3 domain (peak at 465 nm) with a photoluminescence quantum yield (PLQY) as high as 77%. It enables the corresponding perovskite LEDs to deliver stable deep‐blue emission (CIE (0.145, 0.05)) with an external quantum efficiency (EQE) of 2.6%. The findings in this work provide further understanding on the structural and emission properties of quasi‐2D perovskites, which pave a new route to design deep‐blue‐emissive perovskite materials. 相似文献
6.
Christian M. Wolff Pietro Caprioglio Martin Stolterfoht Dieter Neher 《Advanced materials (Deerfield Beach, Fla.)》2019,31(52)
Perovskite solar cells combine high carrier mobilities with long carrier lifetimes and high radiative efficiencies. Despite this, full devices suffer from significant nonradiative recombination losses, limiting their VOC to values well below the Shockley–Queisser limit. Here, recent advances in understanding nonradiative recombination in perovskite solar cells from picoseconds to steady state are presented, with an emphasis on the interfaces between the perovskite absorber and the charge transport layers. Quantification of the quasi‐Fermi level splitting in perovskite films with and without attached transport layers allows to identify the origin of nonradiative recombination, and to explain the VOC of operational devices. These measurements prove that in state‐of‐the‐art solar cells, nonradiative recombination at the interfaces between the perovskite and the transport layers is more important than processes in the bulk or at grain boundaries. Optical pump‐probe techniques give complementary access to the interfacial recombination pathways and provide quantitative information on transfer rates and recombination velocities. Promising optimization strategies are also highlighted, in particular in view of the role of energy level alignment and the importance of surface passivation. Recent record perovskite solar cells with low nonradiative losses are presented where interfacial recombination is effectively overcome—paving the way to the thermodynamic efficiency limit. 相似文献
7.
Pankaj Yadav M. Ibrahim Dar Neha Arora Essa A. Alharbi Fabrizio Giordano Shaik Mohammed Zakeeruddin Michael Grätzel 《Advanced materials (Deerfield Beach, Fla.)》2017,29(40)
Perovskite solar cells (PSCs) based on cesium (Cs)‐ and rubidium (Rb)‐containing perovskite films show highly reproducible performance; however, a fundamental understanding of these systems is still emerging. Herein, this study has systematically investigated the role of Cs and Rb cations in complete devices by examining the transport and recombination processes using current–voltage characteristics and impedance spectroscopy in the dark. As the credibility of these measurements depends on the performance of devices, this study has chosen two different PSCs, (MAFACs)Pb(IBr)3 (MA = CH3NH3+, FA = CH(NH2)2+) and (MAFACsRb)Pb(IBr)3, yielding impressive performances of 19.5% and 21.1%, respectively. From detailed studies, this study surmises that the confluence of the low trap‐assisted charge‐carrier recombination, low resistance offered to holes at the perovskite/2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9‐spirobifluorene interface with a low series resistance (Rs), and low capacitance leads to the realization of higher performance when an extra Rb cation is incorporated into the absorber films. This study provides a thorough understanding of the impact of inorganic cations on the properties and performance of highly efficient devices, and also highlights new strategies to fabricate efficient multiple‐cation‐based PSCs. 相似文献
8.
Ziming Chen Zhenchao Li Chongyang Zhang Xiao‐Fang Jiang Dongcheng Chen Qifan Xue Meiyue Liu Shijian Su Hin‐Lap Yip Yong Cao 《Advanced materials (Deerfield Beach, Fla.)》2018,30(38)
The field of organic–inorganic hybrid perovskite light‐emitting diodes (PeLEDs) has developed rapidly in recent years. Although the performance of PeLEDs continues to improve through film quality control and device optimization, little research has been dedicated to understanding the recombination dynamics in perovskite thin films. Likewise, little has been done to investigate the effects of recombination dynamics on the overall light‐emitting behavior of PeLEDs. Therefore, this study investigates the recombination dynamics of CH3NH3PbI3 thin films with differing crystal sizes by measurement of fluence‐dependent transient absorption dynamics and time‐resolved photoluminescence. The aim is to find out the link between recombination dynamics and device behavior in PeLEDs. It is found that bimolecular and Auger recombination become more efficient as the crystal size decreases and monomolecular recombination rate is affected by the trap density of perovskite. By defining the radiative efficiency Φ(n), which relates to the monomolecular, bimolecular, and Auger recombination, the fundamental recombination properties of CH3NH3PbI3 films are discerned in quantitative terms. These findings help us to understand the light emission behavior of PeLEDs. This study takes an important step toward establishing the relationship between film structure, recombination dynamics, and device behavior for PeLEDs, thereby providing useful insights toward the design of better perovskite devices. 相似文献
9.
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
10.
Feng Zhou Ibrahim Abdelwahab Kai Leng Kian Ping Loh Wei Ji 《Advanced materials (Deerfield Beach, Fla.)》2019,31(48)
Two‐dimensional (2D) perovskites have proved to be promising semiconductors for photovoltaics, photonics, and optoelectronics. Here, a strategy is presented toward the realization of highly efficient, sub‐bandgap photodetection by employing excitonic effects in 2D Ruddlesden–Popper‐type halide perovskites (RPPs). On near resonance with 2D excitons, layered RPPs exhibit degenerate two‐photon absorption (D‐2PA) coefficients as giant as 0.2–0.64 cm MW?1. 2D RPP‐based sub‐bandgap photodetectors show excellent detection performance in the near‐infrared (NIR): a two‐photon‐generated current responsivity up to 1.2 × 104 cm2 W?2 s?1, two orders of magnitude greater than InAsSbP‐pin photodiodes; and a dark current as low as 2 pA at room temperature. More intriguingly, layered‐RPP detectors are highly sensitive to the light polarization of incoming photons, showing a considerable anisotropy in their D‐2PA coefficients (β[001]/β[011] = 2.4, 70% larger than the ratios reported for zinc‐blende semiconductors). By controlling the thickness of the inorganic quantum well, it is found that layered RPPs of (C4H9NH3)2(CH3NH3)Pb2I7 can be utilized for three‐photon photodetection in the NIR region. 相似文献
11.
Sanghyun Paek Peng Qin Yonghui Lee Kyung Taek Cho Peng Gao Giulia Grancini Emad Oveisi Paul Gratia Kasparas Rakstys Shaheen A. Al‐Muhtaseb Christian Ludwig Jaejung Ko Mohammad Khaja Nazeeruddin 《Advanced materials (Deerfield Beach, Fla.)》2017,29(35)
Molecularly engineered novel dopant‐free hole‐transporting materials for perovskite solar cells (PSCs) combined with mixed‐perovskite (FAPbI3)0.85(MAPbBr3)0.15 (MA: CH3NH3+, FA: NH=CHNH3+) that exhibit an excellent power conversion efficiency of 18.9% under AM 1.5 conditions are investigated. The mobilities of FA‐CN, and TPA‐CN are determined to be 1.2 × 10?4 cm2 V?1 s?1 and 1.1 × 10?4 cm2 V?1 s?1, respectively. Exceptional stability up to 500 h is measured with the PSC based on FA‐CN. Additionally, it is found that the maximum power output collected after 1300 h remained 65% of its initial value. This opens up new avenue for efficient and stable PSCs exploring new materials as alternatives to Spiro‐OMeTAD. 相似文献
12.
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
13.
Hsinhan Tsai Wanyi Nie Jean‐Christophe Blancon Constantinos C. Stoumpos Chan Myae Myae Soe Jinkyoung Yoo Jared Crochet Sergei Tretiak Jacky Even Aditya Sadhanala Giovanni Azzellino Roberto Brenes Pulickel M. Ajayan Vladimir Bulović Samuel D. Stranks Richard H. Friend Mercouri G. Kanatzidis Aditya D. Mohite 《Advanced materials (Deerfield Beach, Fla.)》2018,30(6)
State‐of‐the‐art light‐emitting diodes (LEDs) are made from high‐purity alloys of III–V semiconductors, but high fabrication cost has limited their widespread use for large area solid‐state lighting. Here, efficient and stable LEDs processed from solution with tunable color enabled by using phase‐pure 2D Ruddlesden–Popper (RP) halide perovskites with a formula (CH3(CH2)3NH3)2(CH3NH3)n?1PbnI3n+1 are reported. By using vertically oriented thin films that facilitate efficient charge injection and transport, efficient electroluminescence with a radiance of 35 W Sr?1 cm?2 at 744 nm with an ultralow turn‐on voltage of 1 V is obtained. Finally, operational stability tests suggest that phase purity is strongly correlated to stability. Phase‐pure 2D perovskites exhibit >14 h of stable operation at peak operating conditions with no droop at current densities of several Amperes cm?2 in comparison to mixtures of 2D/3D or 3D perovskites, which degrade within minutes. 相似文献
14.
Vertically Oriented 2D Layered Perovskite Solar Cells with Enhanced Efficiency and Good Stability
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Xinqian Zhang Gang Wu Shida Yang Weifei Fu Zhongqiang Zhang Chen Chen Wenqing Liu Jielin Yan Weitao Yang Hongzheng Chen 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(33)
Vertically oriented highly crystalline 2D layered (BA)2(MA)n ?1Pbn I3n +1 (BA = CH3(CH2)3NH3, MA = CH3NH3, n = 3, 4) perovskite thin‐films are fabricated with the aid of ammonium thiocyanate (NH4SCN) additive through one‐step spin‐coating process. The humidity‐stability of the film is certified by the almost unchanged X‐ray diffraction patterns after exposed to humid atmosphere (H r = 55 ± 5%) for 40 d. The photovoltaic devices with the structure of indium tin oxide(ITO)/poly(3,4‐ethylenedioxythiophene):poly(styrene‐sulfonate)/(BA)2(MA)n ?1Pbn I3n +1(n = 3,4)/[6,6]‐phenyl‐C61‐butyric acid methyl ester/Bathocuproine/Ag are fabricated. The devices based on (BA)2(MA)2Pb3I10 perovskite (n = 3) with the precursor composition of BAI:methylammonium iodide:PbI2:NH4SCN = 2:2:3:1 (by molar ratio) show an averaged power conversion efficiency (PCE) of 6.82%. In the case of (BA)2(MA)3Pb4I13 (n = 4), a higher PCE of 8.79% is achieved. Both of the unsealed devices perform unique stability with almost unchanged PCE during the period of storage in purified N2 glove box. This work provides a simple and effective method to enhance the efficiency of the 2D perovskite solar cell. 相似文献
15.
SrCl2 Derived Perovskite Facilitating a High Efficiency of 16% in Hole‐Conductor‐Free Fully Printable Mesoscopic Perovskite Solar Cells
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Hua Zhang Huan Wang Spencer T. Williams Dehua Xiong Wenjun Zhang Chu‐Chen Chueh Wei Chen Alex K.‐Y. Jen 《Advanced materials (Deerfield Beach, Fla.)》2017,29(15)
Despite the breakthrough of over 22% power conversion efficiency demonstrated in organic–inorganic hybrid perovskite solar cells (PVSCs), critical concerns pertaining to the instability and toxicity still remain that may potentially hinder their commercialization. In this study, a new chemical approach using environmentally friendly strontium chloride (SrCl2) as a precursor for perovskite preparation is demonstrated to result in enhanced device performance and stability of the derived hole‐conductor‐free printable mesoscopic PVSCs. The CH3NH3PbI3 perovskite is chemically modified by introducing SrCl2 in the precursor solution. The results from structural, elemental, and morphological analyses show that the incorporation of SrCl2 affords the formation of CH3NH3PbI3(SrCl2)x perovskites endowed with lower defect concentration and better pore filling in the derived mesoscopic PVSCs. The optimized compositional CH3NH3PbI3(SrCl2)0.1 perovskite can substantially enhance the photovoltaic performance of the derived hole‐conductor‐free device to 15.9%, outperforming the value (13.0%) of the pristine CH3NH3PbI3 device. More importantly, the stability of the device in ambient air under illumination is also improved. 相似文献
16.
Highly Efficient p‐i‐n Perovskite Solar Cells Utilizing Novel Low‐Temperature Solution‐Processed Hole Transport Materials with Linear π‐Conjugated Structure
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Yang Li Zheng Xu Suling Zhao Bo Qiao Di Huang Ling Zhao Jiao Zhao Peng Wang Youqin Zhu Xianggao Li Xicheng Liu Xurong Xu 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(35):4902-4908
Alternative low‐temperature solution‐processed hole‐transporting materials (HTMs) without dopant are critical for highly efficient perovskite solar cells (PSCs). Here, two novel small molecule HTMs with linear π‐conjugated structure, 4,4′‐bis(4‐(di‐p‐toyl)aminostyryl)biphenyl (TPASBP) and 1,4′‐bis(4‐(di‐p‐toyl)aminostyryl)benzene (TPASB), are applied as hole‐transporting layer (HTL) by low‐temperature (sub‐100 °C) solution‐processed method in p‐i‐n PSCs. Compared with standard poly(3,4‐ethylenedioxythiophene): poly(styrenesulfonic acid) (PEDOT:PSS) HTL, both TPASBP and TPASB HTLs can promote the growth of perovskite (CH3NH3PbI3) film consisting of large grains and less grain boundaries. Furthermore, the hole extraction at HTL/CH3NH3PbI3 interface and the hole transport in HTL are also more efficient under the conditions of using TPASBP or TPASB as HTL. Hence, the photovoltaic performance of the PSCs is dramatically enhanced, leading to the high efficiencies of 17.4% and 17.6% for the PSCs using TPASBP and TPASB as HTL, respectively, which are ≈40% higher than that of the standard PSC using PEDOT:PSS HTL. 相似文献
17.
Ibrahima Ka Ivy M. Asuo Suchismita Basu Paul Fourmont Dawit M. Gedamu Alain Pignolet Sylvain G. Cloutier Riad Nechache 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(38)
The morphology of hybrid organic–inorganic perovskite films is known to strongly affect the performance of perovskite‐based solar cells. CH3NH3PbI3‐xClx (MAPbI3‐xClx) films have been previously fabricated with 100% surface coverage in glove boxes. In ambient air, fabrication generally relies on solvent engineering to obtain compact films. In contrast, this work explores the potential of altering the perovskites microstructure for solar cell engineering. This work starts with CH3NH3PbI3‐xClx, films with grain morphology carefully controlled by varying the deposition speed during the spin‐coating process to fabricate efficient and partially transparent solar cells. Devices produced with a CH3NH3PbI3‐xClx film and a compact thick top gold electrode reach a maximum efficiency of 10.2% but display a large photocurrent hysteresis. As it is demonstrated, the introduction of different concentrations of bromide in the precursor solution addresses the hysteresis issues and turns the film morphology into a partially transparent interconnected network of 1D microstructures. This approach leads to semitransparent solar cells with negligible hysteresis and efficiencies up to 7.2%, while allowing average transmission of 17% across the visible spectrum. This work demonstrates that the optimization of the perovskites composition can mitigate the hysteresis effects commonly attributed to the charge trapping within the perovskite film. 相似文献
18.
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
19.
Highly Efficient Planar Perovskite Solar Cells Via Interfacial Modification with Fullerene Derivatives
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Yang Dong Wenhua Li Xuejuan Zhang Qian Xu Qian Liu Cuihong Li Zhishan Bo 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(8):1098-1104
Planar heterojunction perovskite solar cells with a high efficiency up to 17.76% are fabricated by modifying the compact TiO2 (c‐TiO2) with a [6,6]‐phenyl‐C61‐butyric acid (PCBA) monolayer. High quality CH3NH3PbI3 films can be easily fabricated on PCBA‐modified c‐TiO2 substrates by a one‐step solution processing method. Significant improvements of the device parameters are observed after PCBA modification. A high open‐circuit voltage (Voc) of 1.16 V has been achieved, indicating that the PCBA monolayer can act as a hole blocking layer to reduce the trap site density atop the c‐TiO2 and the hole recombination at the c‐TiO2/perovskite interface. The enhancement of the fill factor, as well as the partial quenching of the fluorescence of perovskite after modification with PCBA, reveals that the charge extraction is improved. 相似文献
20.
Picosecond Capture of Photoexcited Electrons Improves Photovoltaic Conversion in MAPbI3:C70‐Doped Planar and Mesoporous Solar Cells
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Saba Gharibzadeh Franco Valduga de Almeida Camargo Cristina Roldán‐Carmona Grégoire Clément Gschwend Jorge Pascual Ramón Tena‐Zaera Giulio Cerullo Giulia Grancini Mohammad Khaja Nazeeruddin 《Advanced materials (Deerfield Beach, Fla.)》2018,30(40)
In this work, solar cells based on methylammonium lead iodide (MAPbI3) doped in solution with C70 fullerene in a mesoporous as well as planar electron‐transporting layer (ETL)‐free architecture are realized, showcasing in the latter case a record efficiency of 15.7% and an improved open‐circuit voltage (VOC). Contrary to the bulk heterojunction previously reported, the C70 molecules do not phase segregate and they are rather finely dispersed in the perovskite film, possibly infiltrating at the grain boundaries, while assisting the growth of a highly uniform perovskite layer. By means of time‐resolved femtosecond‐to‐nanosecond optical spectroscopy, with an extended spectral coverage, it is observed that electrons photogenerated in the perovskite are transferred to C70 with a time constant of 20 ps. Despite being captured by C70, electrons are not deeply trapped and can potentially bounce back into the perovskite, as suggested by the high fill factor and enhanced VOC of the MAPbI3:C70 solar cells, especially in the case of the ETL‐free device configuration. 相似文献