共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
Ferroelectric Properties of Perovskite Thin Films and Their Implications for Solar Energy Conversion
Holger Rhm Tobias Leonhard Alexander D. Schulz Susanne Wagner Michael J. Hoffmann Alexander Colsmann 《Advanced materials (Deerfield Beach, Fla.)》2019,31(26)
Whether or not methylammonium lead iodide (MAPbI3) is a ferroelectric semiconductor has caused controversy in the literature, fueled by many misunderstandings and imprecise definitions. Correlating recent literature reports and generic crystal properties with the authors' experimental evidence, the authors show that MAPbI3 thin‐films are indeed semiconducting ferroelectrics and exhibit spontaneous polarization upon transition from the cubic high‐temperature phase to the tetragonal phase at room temperature. The polarization is predominantly oriented in‐plane and is organized in characteristic domains as probed with piezoresponse force microscopy. Drift‐diffusion simulations based on experimental patterns of polarized domains indicate a reduction of the Shockley–Read–Hall recombination of charge carriers within the perovskite grains due to the ferroelectric built‐in field and allow reproduction of the electrical solar cell properties. 相似文献
3.
Iodine Vacancy Redistribution in Organic–Inorganic Halide Perovskite Films and Resistive Switching Effects 下载免费PDF全文
Organic–inorganic halide perovskite (OHP) materials, for example, CH3NH3PbI3 (MAPbI3), have attracted significant interest for applications such as solar cells, photodectors, light‐emitting diodes, and lasers. Previous studies have shown that charged defects can migrate in perovskites under an electric field and/or light illumination, potentially preventing these devices from practical applications. Understanding and control of the defect generation and movement will not only lead to more stable devices but also new device concepts. Here, it is shown that the formation/annihilation of iodine vacancies (VI's) in MAPbI3 films, driven by electric fields and light illumination, can induce pronounced resistive switching effects. Due to a low diffusion energy barrier (≈0.17 eV), the VI's can readily drift under an electric field, and spontaneously diffuse with a concentration gradient. It is shown that the VI diffusion process can be suppressed by controlling the affinity of the contact electrode material to I? ions, or by light illumination. An electrical‐write and optical‐erase memory element is further demonstrated by coupling ion migration with electric fields and light illumination. These results provide guidance toward improved stability and performance of perovskite‐based optoelectronic systems, and can lead to the development of solid‐state devices that couple ionics, electronics, and optics. 相似文献
4.
Epitaxial Bi2FeCrO6 Multiferroic Thin Film as a New Visible Light Absorbing Photocathode Material 下载免费PDF全文
Shun Li Bandar AlOtaibi Wei Huang Zetian Mi Nick Serpone Riad Nechache Federico Rosei 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(32):4018-4026
Ferroelectric materials have been studied increasingly for solar energy conversion technologies due to the efficient charge separation driven by the polarization induced internal electric field. However, their insufficient conversion efficiency is still a major challenge. Here, a photocathode material of epitaxial double perovskite Bi2FeCrO6 multiferroic thin film is reported with a suitable conduction band position and small bandgap (1.9–2.1 eV), for visible‐light‐driven reduction of water to hydrogen. Photoelectrochemical measurements show that the highest photocurrent density up to ?1.02 mA cm?2 at a potential of ?0.97 V versus reversible hydrogen electrode is obtained in p‐type Bi2FeCrO6 thin film photocathode grown on SrTiO3 substrate under AM 1.5G simulated sunlight. In addition, a twofold enhancement of photocurrent density is obtained after negatively poling the Bi2FeCrO6 thin film, as a result of modulation of the band structure by suitable control of the internal electric field gradient originating from the ferroelectric polarization in the Bi2FeCrO6 films. The findings validate the use of multiferroic Bi2FeCrO6 thin films as photocathode materials, and also prove that the manipulation of internal fields through polarization in ferroelectric materials is a promising strategy for the design of improved photoelectrodes and smart devices for solar energy conversion. 相似文献
5.
Stefan Kilper Timotheus Jahnke Marc Aulich Zaklina Burghard Dirk Rothenstein Joachim Bill 《Advanced materials (Deerfield Beach, Fla.)》2019,31(6)
Polycrystalline piezo‐active materials only exhibit a high macroscopic piezoresponse if they consist of particles with oriented crystal directions and aligned intrinsic dipole moments. For ferroelectric materials, the postsynthesis alignment of the dipoles is generally achieved by electric poling procedures. However, there are numerous technically interesting non‐ferroelectric piezo‐active materials like zinc oxide (ZnO). These materials demand the alignment of their intrinsic dipoles during the fabrication process. Therefore, in situ‐poling techniques have to be developed. This study utilizes genetically modified M13 phage templates for the generation of force fields, which directly control the ZnO dipole poling. By genetic modification of M13 phage template, the piezoelectric response of the ZnO/M13 phage hybrid nanowire is doubled compared to the hybrid nanowire based on unmodified M13 wild type (wt) phage templates. Thus, the formation of piezo‐active domains consisting of oriented ZnO nanocrystals is directly induced by the genetic modification. By the combination of the fiber‐like structure of individual M13 phages with the bioenhanced electromechanical properties of ZnO, hybrid nanowires with a length of ≈1.1 µm and a thickness of ≈63.5 nm are fabricated with a high piezoelectric coefficient of up to d33 = 7.8 pm V?1 for genetically modified M13 phage templates. 相似文献
6.
Highly Efficient 2D/3D Hybrid Perovskite Solar Cells via Low‐Pressure Vapor‐Assisted Solution Process 下载免费PDF全文
Ming‐Hsien Li Hung‐Hsiang Yeh Yu‐Hsien Chiang U‐Ser Jeng Chun‐Jen Su Hung‐Wei Shiu Yao‐Jane Hsu Nobuhiro Kosugi Takuji Ohigashi Yu‐An Chen Po‐Shen Shen Peter Chen Tzung‐Fang Guo 《Advanced materials (Deerfield Beach, Fla.)》2018,30(30)
The fabrication of multidimensional organometallic halide perovskite via a low‐pressure vapor‐assisted solution process is demonstrated for the first time. Phenyl ethyl‐ammonium iodide (PEAI)‐doped lead iodide (PbI2) is first spin‐coated onto the substrate and subsequently reacts with methyl‐ammonium iodide (MAI) vapor in a low‐pressure heating oven. The doping ratio of PEAI in MAI‐vapor‐treated perovskite has significant impact on the crystalline structure, surface morphology, grain size, UV–vis absorption and photoluminescence spectra, and the resultant device performance. Multiple photoluminescence spectra are observed in the perovskite film starting with high PEAI/PbI2 ratio, which suggests the coexistence of low‐dimensional perovskite (PEA2MAn?1PbnI3n+1) with various values of n after vapor reaction. The dimensionality of the as‐fabricated perovskite film reveals an evolution from 2D, hybrid 2D/3D to 3D structure when the doping level of PEAI/PbI2 ratio varies from 2 to 0. Scanning electron microscopy images and Kelvin probe force microscopy mapping show that the PEAI‐containing perovskite grain is presumably formed around the MAPbI3 perovskite grain to benefit MAPbI3 grain growth. The device employing perovskite with PEAI/PbI2 = 0.05 achieves a champion power conversion efficiency of 19.10% with an open‐circuit voltage of 1.08 V, a current density of 21.91 mA cm?2, and a remarkable fill factor of 80.36%. 相似文献
7.
Meng Li Ying‐Guo Yang Zhao‐Kui Wang Tin Kang Qiong Wang Silver‐Hamill Turren‐Cruz Xing‐Yu Gao Chain‐Shu Hsu Liang‐Sheng Liao Antonio Abate 《Advanced materials (Deerfield Beach, Fla.)》2019,31(25)
Halide perovskite films processed from solution at low‐temperature offer promising opportunities to make flexible solar cells. However, the brittleness of perovskite films is an issue for mechanical stability in flexible devices. Herein, photo‐crosslinked [6,6]‐phenylC61‐butyric oxetane dendron ester (C‐PCBOD) is used to improve the mechanical stability of methylammonium lead iodide (MAPbI3) perovskite films. Also, it is demonstrated that C‐PCBOD passivates the grain boundaries, which reduces the formation of trap states and enhances the environmental stability of MAPbI3. Thus, MAPbI3 perovskite solar cells are prepared on solid and flexible substrates with record efficiencies of 20.4% and 18.1%, respectively, which are among the highest ever reported for MAPbI3 on both flexible and solid substrates. The result of this work provides a step improvement toward stable and efficient flexible perovskite solar cells. 相似文献
8.
Dual‐Phase CsPbBr3–CsPb2Br5 Perovskite Thin Films via Vapor Deposition for High‐Performance Rigid and Flexible Photodetectors 下载免费PDF全文
Guoqing Tong Huan Li Danting Li Zhifeng Zhu Enze Xu Guopeng Li Linwei Yu Jun Xu Yang Jiang 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(7)
Inorganic perovskites with special semiconducting properties and structures have attracted great attention and are regarded as next generation candidates for optoelectronic devices. Herein, using a physical vapor deposition process with a controlled excess of PbBr2, dual‐phase all‐inorganic perovskite composite CsPbBr3–CsPb2Br5 thin films are prepared as light‐harvesting layers and incorporated in a photodetector (PD). The PD has a high responsivity and detectivity of 0.375 A W?1 and 1011 Jones, respectively, and a fast response time (from 10% to 90% of the maximum photocurrent) of ≈280 µs/640 µs. The device also shows an excellent stability in air for more than 65 d without encapsulation. Tetragonal CsPb2Br5 provides satisfactory passivation to reduce the recombination of the charge carriers, and with its lower free energy, it enhances the stability of the inorganic perovskite devices. Remarkably, the same inorganic perovskite photodetector is also highly flexible and exhibits an exceptional bending performance (>1000 cycles). These results highlight the great potential of dual‐phase inorganic perovskite films in the development of optoelectronic devices, especially for flexible device applications. 相似文献
9.
In Situ Real‐Time Study of the Dynamic Formation and Conversion Processes of Metal Halide Perovskite Films 下载免费PDF全文
Ke Meng Longlong Wu Zhou Liu Xiao Wang Qiaofei Xu Youdi Hu Sanfeng He Xiaolong Li Tao Li Gang Chen 《Advanced materials (Deerfield Beach, Fla.)》2018,30(11)
Metal halide perovskite solar cells (PSCs) have advanced to the forefront of solution‐processed photovoltaic techniques and made stunning progress in power conversion efficiency (PCE). Further improvements in device performances rely on perfecting the structure and morphology of perovskite films. However, undesirable defects such as pinholes and grain boundaries are often created in film preparations due to lack of knowledge of the precise reaction mechanism. Here, in situ grazing‐incidence X‐ray diffraction (GI‐XRD) investigations are performed, facilitated by other techniques, on the formation of the widely adopted MAPbI3 (MA = methylammonium) perovskite films from their intermediate adduct (IA) phases. The influences of solvent vapor atmospheres on MAPbI3 films are also systematically investigated, where the dynamic conversion processes between different phases are visualized in real time. Further in situ GI‐XRD and infrared spectroscopy measurements reveal that the IA phases contain both N,N‐dimethylformamide and dimethyl sulfoxide (DMSO) as coordinating molecules. By tuning the DMSO concentration in perovskite precursors, the ideal perovskite film is formed and the best PCE is achieved for the planar MAPbI3‐based PSCs. These findings highlight the role of IA phases and the effect of solvent atmospheres on the quality of perovskite films, providing direct insights into their growth mechanism. 相似文献
10.
Controlled Substitution of Chlorine for Iodine in Single‐Crystal Nanofibers of Mixed Perovskite MAPbI3–xClx 下载免费PDF全文
Haihua Zhang Qing Liao Xuedong Wang Ke Hu Jiannian Yao Hongbing Fu 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(28):3780-3787
Longer carrier diffusion length and improved power conversion efficiency have been reported for thin‐film solar cell of organolead mixed‐halide perovskite MAPbI3– x Cl x in comparison with MAPbI3. Instead of substituting I in the MAPbI3 lattice, Cl‐incorporation has been shown to mainly improve the film morphology of perovskite absorber. Well‐defined crystal structure, adjustable composition (x), and regular morphology, remains a formidable task. Herein, a facile solution‐assembly method is reported for synthesizing single‐crystalline nanofibers (NFs) of tetragonal‐lattice MAPbI3– x Cl x with the Cl‐content adjustable between 0 ≤ x ≤ 0.75, leading to a gradual blueshift of the absorption and photoluminescence maxima from x = 0 to 0.75. The photoresponsivity (R) of MAPbI3 NFs keeps almost unchanging at a value independent of the white‐light illumination intensity (P). In contrast, R of MAPbI3– x Cl x NFs decreases rapidly with increasing both the x and P values, indicating Cl‐substitution increases the recombination traps of photogenerated free electrons and holes. This study provides a model system to examine the role of extrinsic Cl ions in both perovskite crystallography and optoelectronic properties. 相似文献
11.
In this study, a facile and effective approach to synthesize high‐quality perovskite‐quantum dots (QDs) hybrid film is demonstrated, which dramatically improves the photovoltaic performance of a perovskite solar cell (PSC). Adding PbS QDs into CH3NH3PbI3 (MAPbI3) precursor to form a QD‐in‐perovskite structure is found to be beneficial for the crystallization of perovskite, revealed by enlarged grain size, reduced fragmentized grains, enhanced characteristic peak intensity, and large percentage of (220) plane in X‐ray diffraction patterns. The hybrid film also shows higher carrier mobility, as evidenced by Hall Effect measurement. By taking all these advantages, the PSC based on MAPbI3‐PbS hybrid film leads to an improvement in power conversion efficiency by 14% compared to that based on pure perovskite, primarily ascribed to higher current density and fill factor (FF). Ultimately, an efficiency reaching up to 18.6% and a FF of over ≈0.77 are achieved based on the PSC with hybrid film. Such a simple hybridizing technique opens up a promising method to improve the performance of PSCs, and has strong potential to be applied to prepare other hybrid composite materials. 相似文献
12.
Composite of CH3NH3PbI3 with Reduced Graphene Oxide as a Highly Efficient and Stable Visible‐Light Photocatalyst for Hydrogen Evolution in Aqueous HI Solution 下载免费PDF全文
Yaqiang Wu Peng Wang Xianglin Zhu Qianqian Zhang Zeyan Wang Yuanyuan Liu Guizheng Zou Ying Dai Myung‐Hwan Whangbo Baibiao Huang 《Advanced materials (Deerfield Beach, Fla.)》2018,30(7)
A facile and efficient photoreduction method is employed to synthesize the composite of methylammonium lead iodide perovskite (MAPbI3) with reduced graphene oxide (rGO). This MAPbI3/rGO composite is shown to be an outstanding visible‐light photocatalyst for H2 evolution in aqueous HI solution saturated with MAPbI3. Powder samples of MAPbI3/rGO (100 mg) show a H2 evolution rate of 93.9 µmol h?1, which is 67 times faster than that of pristine MAPbI3, under 120 mW cm?2 visible‐light (λ ≥ 420 nm) illumination, and the composite is highly stable showing no significant decrease in the catalytic activity after 200 h (i.e., 20 cycles) of repeated H2 evolution experiments. The electrochemiluminescence performance of MAPbI3 is investigated to explore the charge transfer process, to find that the photogenerated electrons in MAPbI3 are transferred to the rGO sites, where protons are reduced to H2. 相似文献
13.
Symmetrization of the Crystal Lattice of MAPbI3 Boosts the Performance and Stability of Metal–Perovskite Photodiodes 下载免费PDF全文
Zhifang Shi Yi Zhang Chao Cui Binghan Li Wenjia Zhou Zhijun Ning Qixi Mi 《Advanced materials (Deerfield Beach, Fla.)》2017,29(30)
Semiconducting lead triiodide perovskites (A PbI3) have shown remarkable performance in applications including photovoltaics and electroluminescence. Despite many theoretical possibilities for A + in A PbI3, the current experimental knowledge is largely limited to two of these materials: methylammonium (MA+) and formamidinium (FA+) lead triiodides, neither of which adopts the ideal, cubic perovskite structure at room temperature. Here, a volume‐based criterion is proposed for cubic A PbI3 to be stable, and two perovskite materials MA1?x EAx PbI3 (MEPI, EA+ = ethylammonium) and MA1?y DMAy PbI3 (MDPI, DMA+ = dimethylammonium) are introduced. Powder and single‐crystal X‐ray diffraction (XRD) results reveal that MEPI and MDPI are solid solutions possessing the cubic perovskite structure, and the EA+ and DMA+ cations play similar roles in the symmetrization of the crystal lattice of MAPbI3. Single crystals of MEPI and MDPI are grown and made into plates of a range of thicknesses, and then into metal–perovskite photodiodes. These devices exhibit tripled diffusion lengths and about tenfold enhancement in stability against moisture, both relative to the current benchmark MAPbI3. In this study, the systematic approach to materials design and device fabrication greatly expands the candidate pool of perovskite semiconductors, and paves the way for high‐performance, single‐crystal perovskite devices including solar cells and light emitters. 相似文献
14.
In Situ Observation of Crystallization of Methylammonium Lead Iodide Perovskite from Microdroplets 下载免费PDF全文
Yahui Li Zhenhao Zhao Feng Lin Xiaobing Cao Xian Cui Jinquan Wei 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(26)
It is of great importance to investigate the crystallization of organometallic perovskite from solution for enhancing performance of perovskite solar cells. Here, this study develops a facile method for in situ observation of crystallization and growth of the methylammonium lead iodide (MAPbI3) perovskite from microdroplets ejected by an alternating viscous and inertial force jetting method. It is found that there are two crystallization modes when MAPbI3 grows from the CH3NH3I (MAI)/PbI2/N,N‐dimethylformamide (DMF) solution: needle precursors and granular perovskites. Generally, needle Lewis adduct of MAPbI3·DMF tends to nucleate and grow from the solution due to low solubility of PbI2. The growth of MAPbI3·DMF depends on both the concentration of MAI and temperature. It tends to form large perovskite domains on substrates at high temperature. The MAPbI3·DMF coverts to nanocrystalline perovskite due to lattice shrinkage when DMF molecules escape from the Lewis adduct. Granular perovskite can also directly nucleate from the solution at high concentration of MAI due to compositional segregation. 相似文献
15.
Large‐Scale Synthesis of Freestanding Layer‐Structured PbI2 and MAPbI3 Nanosheets for High‐Performance Photodetection 下载免费PDF全文
Changyong Lan Ruoting Dong Ziyao Zhou Lei Shu Dapan Li SenPo Yip Johnny C. Ho 《Advanced materials (Deerfield Beach, Fla.)》2017,29(39)
Recently, due to the possibility of thinning down to the atomic thickness to achieve exotic properties, layered materials have attracted extensive research attention. In particular, PbI2, a kind of layered material, and its perovskite derivatives, CH3NH3PbI3 (i.e., MAPbI3), have demonstrated impressive photoresponsivities for efficient photodetection. Herein, the synthesis of large‐scale, high‐density, and freestanding PbI2 nanosheets is demonstrated by manipulating the microenvironment during physical vapor deposition. In contrast to conventional two‐dimensional (2D) growth along the substrate surface, the essence here is the effective nucleation of microplanes with different angles relative to the in‐plane direction of underlying rough‐surfaced substrates. When configured into photodetectors, the fabricated device exhibits a photoresponsivity of 410 mA W?1, a detectivity of 3.1 × 1011 Jones, and a fast response with the rise and decay time constants of 86 and 150 ms, respectively, under a wavelength of 405 nm. These PbI2 nanosheets can also be completely converted into MAPbI3 materials via chemical vapor deposition with an improved photoresponsivity up to 40 A W?1. All these performance parameters are comparable to those of state‐of‐the‐art layered‐material‐based photodetectors, revealing the technological potency of these freestanding nanosheets for next‐generation high‐performance optoelectronics. 相似文献
16.
Stability of Halide Perovskite Solar Cell Devices: In Situ Observation of Oxygen Diffusion under Biasing 下载免费PDF全文
Hee Joon Jung Daehan Kim Sungkyu Kim Joonsuk Park Vinayak P. Dravid Byungha Shin 《Advanced materials (Deerfield Beach, Fla.)》2018,30(39)
Using in situ electrical biasing transmission electron microscopy, structural and chemical modification to n–i–p‐type MAPbI3 solar cells are examined with a TiO2 electron‐transporting layer caused by bias in the absence of other stimuli known to affect the physical integrity of MAPbI3 such as moisture, oxygen, light, and thermal stress. Electron energy loss spectroscopy (EELS) measurements reveal that oxygen ions are released from the TiO2 and migrate into the MAPbI3 under a forward bias. The injection of oxygen is accompanied by significant structural transformation; a single‐crystalline MAPbI3 grain becomes amorphous with the appearance of PbI2. Withdrawal of oxygen back to the TiO2, and some restoration of the crystallinity of the MAPbI3, is observed after the storage in dark under no bias. A subsequent application of a reverse bias further removes more oxygen ions from the MAPbI3. Light current–voltage measurements of perovskite solar cells exhibit poorer performance after elongated forward biasing; recovery of the performance, though not complete, is achieved by subsequently applying a negative bias. The results indicate negative impacts on the device performance caused by the oxygen migration to the MAPbI3 under a forward bias. This study identifies a new degradation mechanism intrinsic to n–i–p MAPbI3 devices with TiO2. 相似文献
17.
Guanqi Tang Peng You Qidong Tai Anneng Yang Jiupeng Cao Fangyuan Zheng Zhiwen Zhou Jiong Zhao Paddy Kwok Leung Chan Feng Yan 《Advanced materials (Deerfield Beach, Fla.)》2019,31(24)
The quality of perovskite films is critical to the performance of perovskite solar cells. However, it is challenging to control the crystallinity and orientation of solution‐processed perovskite films. Here, solution‐phase van der Waals epitaxy growth of MAPbI3 perovskite films on MoS2 flakes is reported. Under transmission electron microscopy, in‐plane coupling between the perovskite and the MoS2 crystal lattices is observed, leading to perovskite films with larger grain size, lower trap density, and preferential growth orientation along (110) normal to the MoS2 surface. In perovskite solar cells, when perovskite active layers are grown on MoS2 flakes coated on hole‐transport layers, the power conversion efficiency is substantially enhanced for 15%, relatively, due to the increased crystallinity of the perovskite layer and the improved hole extraction and transfer rate at the interface. This work paves a way for preparing high‐performance perovskite solar cells and other optoelectronic devices by introducing 2D materials as interfacial layers. 相似文献
18.
Picosecond Capture of Photoexcited Electrons Improves Photovoltaic Conversion in MAPbI3:C70‐Doped Planar and Mesoporous Solar Cells 下载免费PDF全文
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
19.
Jianguo Sun Bin Li Long Hu Junjun Guo Xufeng Ling Xuliang Zhang Chi Zhang Xianxin Wu Hehe Huang Chenxu Han Xinfeng Liu Youyong Li Shujuan Huang Tom Wu Jianyu Yuan Wanli Ma 《Advanced materials (Deerfield Beach, Fla.)》2023,35(1):2206047
Solution processable semiconductors like organics and emerging lead halide perovskites (LHPs) are ideal candidates for photovoltaics combining high performance and flexibility with reduced manufacturing cost. Moreover, the study of hybrid semiconductors would lead to advanced structures and deep understanding that will propel this field even further. Herein, a novel device architecture involving block copolymer/perovskite hybrid bulk heterointerfaces is investigated, such a modification could enhance light absorption, create an energy level cascade, and provides a thin hydrophobic layer, thus enabling enhanced carrier generation, promoting energy transfer and preventing moisture invasion, respectively. The resulting hybrid block copolymer/perovskite solar cell exhibits a champion efficiency of 24.07% for 0.0725 cm2-sized devices and 21.44% for 1 cm2-sized devices, respectively, together with enhanced stability, which is among the highest reports of organic/perovskite hybrid devices. More importantly, this approach has been effectively extended to other LHPs with different chemical compositions like MAPbI3 and CsPbI3, which may shed light on the design of highly efficient block copolymer/perovskite hybrid materials and architectures that would overcome current limitations for realistic application exploration. 相似文献
20.
Insights about the Absence of Rb Cation from the 3D Perovskite Lattice: Effect on the Structural,Morphological, and Photophysical Properties and Photovoltaic Performance 下载免费PDF全文
Ryusuke Uchida Silvia Binet Neha Arora Gwenole Jacopin Mohammad Hayal Alotaibi Andreas Taubert Shaik M. Zakeeruddin M. Ibrahim Dar Michael Graetzel 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(36)
Efficiencies >20% are obtained from the perovskite solar cells (PSCs) employing Cs+ and Rb+ based perovskite compositions; therefore, it is important to understand the effect of these inorganic cations specifically Rb+ on the properties of perovskite structures. Here the influence of Cs+ and Rb+ is elucidated on the structural, morphological, and photophysical properties of perovskite structures and the photovoltaic performances of resulting PSCs. Structural, photoluminescence (PL), and external quantum efficiency studies establish the incorporation of Cs+ (x < 10%) but amply rule out the possibility of Rb‐incorporation into the MAPbI3 (MA = CH3NH3 +) lattice. Moreover, morphological studies and time‐resolved PL show that both Cs+ and Rb+ detrimentally affect the surface coverage of MAPbI3 layers and charge‐carrier dynamics, respectively, by influencing nucleation density and by inducing nonradiative recombination. In addition, differential scanning calorimetry shows that the transition from orthorhombic to tetragonal phase occurring around 160 K requires more thermal energy for the Cs‐containing MAPbI3 systems compared to the pristine MAPbI3. Investigation including mixed halide (I/Br) and mixed cation A‐cation based compositions further confirms the absence of Rb+ from the 3D‐perovskite lattice. The fundamental insights gained through this work will be of great significance to further understand highly promising perovskite compositions. 相似文献