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1.
Xingtao Wang Yong Wang Taiyang Zhang Xiaomin Liu Yixin Zhao 《Angewandte Chemie (International ed. in English)》2020,59(4):1469-1473
The reduced dimension perovskite including 2D perovskites are one of the most promising strategies to stabilize lead halide perovskite. A mixed‐cation 2D perovskite based on a steric phenyltrimethylammonium (PTA) cation is presented. The PTA‐MA mixed‐cation 2D perovskite of PTAMAPbI4 can be formed on the surface of MAPbI3 (PTAI‐MAPbI3) by controllable PTAI intercalation by either spin coating or soaking. The PTAMAPbI4 capping layer can not only passivate PTAI‐MAPbI3 perovskite but also act as MA+ locker to inhibit MAI extraction and significantly enhance the stability. The highly stable PTAI‐MAPbI3 based perovskite solar cells exhibit a reproducible photovoltaic performance with a champion PCE of 21.16 %. Such unencapsulated devices retain 93 % of initial efficiency after 500 h continuous illumination. This steric mixed‐cation 2D perovskite as MA+ locker to stabilize the MAPbI3 is a promising strategy to design stable and high‐performance hybrid lead halide perovskites. 相似文献
2.
Xingtao Wang Dr. Yong Wang Dr. Taiyang Zhang Xiaomin Liu Prof. Yixin Zhao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(4):1485-1489
The reduced dimension perovskite including 2D perovskites are one of the most promising strategies to stabilize lead halide perovskite. A mixed-cation 2D perovskite based on a steric phenyltrimethylammonium (PTA) cation is presented. The PTA-MA mixed-cation 2D perovskite of PTAMAPbI4 can be formed on the surface of MAPbI3 (PTAI-MAPbI3) by controllable PTAI intercalation by either spin coating or soaking. The PTAMAPbI4 capping layer can not only passivate PTAI-MAPbI3 perovskite but also act as MA+ locker to inhibit MAI extraction and significantly enhance the stability. The highly stable PTAI-MAPbI3 based perovskite solar cells exhibit a reproducible photovoltaic performance with a champion PCE of 21.16 %. Such unencapsulated devices retain 93 % of initial efficiency after 500 h continuous illumination. This steric mixed-cation 2D perovskite as MA+ locker to stabilize the MAPbI3 is a promising strategy to design stable and high-performance hybrid lead halide perovskites. 相似文献
3.
Tian Wu Junnan Li Yatao Zou Hao Xu Kaichuan Wen Shanshan Wan Sai Bai Tao Song John A. McLeod Steffen Duhm Feng Gao Baoquan Sun 《Angewandte Chemie (International ed. in English)》2020,59(10):4099-4105
Defect passivation has been demonstrated to be effective in improving the radiative recombination of charge carriers in perovskites, and consequently, the device performance of the resultant perovskite light‐emitting diodes (LEDs). State‐of‐the‐art useful passivation agents in perovskite LEDs are mostly organic chelating molecules that, however, simultaneously sacrifice the charge‐transport properties and thermal stability of the resultant perovskite emissive layers, thereby deteriorating performance, and especially the operational stability of the devices. We demonstrate that lithium halides can efficiently passivate the defects generated by halide vacancies and reduce trap state density, thereby suppressing ion migration in perovskite films. Efficient green perovskite LEDs based on all‐inorganic CsPbBr3 perovskite with a peak external quantum efficiency of 16.2 %, as well as a high maximum brightness of 50 270 cd m?2, are achieved. Moreover, the device shows decent stability even under a brightness of 104 cd m?2. We highlight the universal applicability of defect passivation using lithium halides, which enabled us to improve the efficiency of blue and red perovskite LEDs. 相似文献
4.
Alloying n‐Butylamine into CsPbBr3 To Give a Two‐Dimensional Bilayered Perovskite Ferroelectric Material 下载免费PDF全文
Zhenyue Wu Chengmin Ji Dr. Lina Li Dr. Jintao Kong Prof. Zhihua Sun Prof. Sangen Zhao Sasa Wang Prof. Maochun Hong Prof. Junhua Luo 《Angewandte Chemie (International ed. in English)》2018,57(27):8140-8143
Cesium‐lead halide perovskites (e.g. CsPbBr3) have gained attention because of their rich physical properties, but their bulk ferroelectricity remains unexplored. Herein, by alloying flexible organic cations into the cubic CsPbBr3, we design the first cesium‐based two‐dimensional (2D) perovskite ferroelectric material with both inorganic alkali metal and organic cations, (C4H9NH3)2CsPb2Br7 ( 1 ). Strikingly, 1 shows a high Curie temperature (Tc=412 K) above that of BaTiO3 (ca. 393 K) and notable spontaneous polarization (ca. 4.2 μC cm?2), triggered by not only the ordering of organic cations but also atomic displacement of inorganic Cs+ ions. To our knowledge, such a 2D bilayered Cs+‐based metal–halide perovskite ferroelectric material with inorganic and organic cations is unprecedented. 1 also shows photoelectric semiconducting behavior with large “on/off” ratios of photoconductivity (>103). 相似文献
5.
Jialong Duan Yuanyuan Zhao Yudi Wang Xiya Yang Qunwei Tang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(45):16293-16297
The all‐inorganic CsPbBr3 perovskite solar cell (PSC) is a promising solution to balance the high efficiency and poor stability of state‐of‐the‐art organic–inorganic PSCs. Setting inorganic hole‐transporting layers at the perovskite/electrode interface decreases charge carrier recombination without sacrificing superiority in air. Now, M‐substituted, p‐type inorganic Cu(Cr,M)O2 (M=Ba2+, Ca2+, or Ni2+) nanocrystals with enhanced hole‐transporting characteristics by increasing interstitial oxygen effectively extract holes from perovskite. The all‐inorganic CsPbBr3 PSC with a device structure of FTO/c‐TiO2/m‐TiO2/CsPbBr3/Cu(Cr,M)O2/carbon achieves an efficiency up to 10.18 % and it increases to 10.79 % by doping Sm3+ ions into perovskite halide, which is much higher than 7.39 % for the hole‐free device. The unencapsulated Cu(Cr,Ba)O2‐based PSC presents a remarkable stability in air in either 80 % humidity over 60 days or 80 °C conditions over 40 days or light illumination for 7 days. 相似文献
6.
Wuqian Guo Xitao Liu Shiguo Han Yi Liu Zhiyun Xu Maochun Hong Junhua Luo Zhihua Sun 《Angewandte Chemie (International ed. in English)》2020,59(33):13879-13884
Although two‐dimensional (2D) metal–halide double perovskites display versatile physical properties due to their huge structural compatibility, room‐temperature ferroelectric behavior has not yet been reported for this fascinating family. Here, we designed a room‐temperature ferroelectric material composed of 2D halide double perovskites, (chloropropylammonium)4AgBiBr8, using an organic asymmetric dipolar ligand. It exhibits concrete ferroelectricity, including a Curie temperature of 305 K and a notable spontaneous polarization of ≈3.2 μC cm?2, triggered by dynamic ordering of the organic cation and the tilting motion of heterometallic AgBr6/BiBr6 octahedra. Besides, the alternating array of inorganic perovskite sheets and organic cations endows large mobility‐lifetime product (μτ=1.0×10?3 cm2 V?1) for detecting X‐ray photons, which is almost tenfold higher than that of CH3NH3PbI3 wafers. As far as we know, this is the first study on an X‐ray‐sensitive ferroelectric material composed of 2D halide double perovskites. Our findings afford a promising platform for exploring new ferroelectric materials toward further device applications. 相似文献
7.
Jieni Li Henan Li Lai Liu Huizhen Yao Bingbing Tian Chenliang Su Haizhe Zhong Ye Wang Lifu Zhang Yumeng Shi 《化学:亚洲杂志》2019,14(16):2861-2868
Organometallic halide perovskites have attracted great research interest as light‐active materials for use in optoelectronics. Here, we report a high‐performance photoconductor based on a methylammonium lead iodide (MAPbI3) film that was prepared from a methylamine‐treated MAPbI3/PbI2 perovskite film. An ultrahigh responsivity of 3.6 A W?1 and detectivity of 5.4×1012 Jones were obtained for the film under 0.5 mW cm?2 white‐light illumination. In addition, under 420 nm light irradiation, the film exhibited its highest responsivity and detectivity of 30 A W?1 and 2.4×1014 Jones, respectively. The excellent photo‐response performance results from the improved electronic quality and suppressed nonradiative recombination channels of the treated perovskite thin film. 相似文献
8.
Zhenzhen Zhang Yuying Yang Yingying Wang Lanlan Yang Qi Li Langxing Chen Dongsheng Xu 《Angewandte Chemie (International ed. in English)》2020,59(41):18136-18139
The lead‐free halide perovskite A3Sb2Br9 is utilized as a photocatalyst for the first time for C(sp3)?H bond activation. A3Sb2Br9 nanoparticles (A3Sb2Br9 NPs) with different ratios of Cs and CH3NH3 (MA) show different photocatalytic activities for toluene oxidation and the photocatalytic performance is enhanced when increasing the amount of Cs. The octahedron distortion caused by A‐site cations can change the electronic properties of X‐site ions and further affect the electron transfer from toluene molecules to Br sites. After the regulation of A‐site cations, the photocatalytic activity is higher with A3Sb2Br9 NPs than that with classic photocatalysts (TiO2, WO3, and CdS). The main active species involved in photocatalytic oxidation of toluene are photogenerated holes (h+) and superoxide anions (.O2?). The octahedron distortion by A‐site cations affecting photocatalytic activity remains unique and is also a step forward for understanding more about halide‐perovskite‐based photocatalysis. The relationship between octahedron distortion and photocatalysis can also guide the design of new photocatalytic systems involving other halide perovskites. 相似文献
9.
Kaushik Kundu Paribesh Acharyya Krishnendu Maji Ranjan Sasmal Sarit S. Agasti Kanishka Biswas 《Angewandte Chemie (International ed. in English)》2020,59(31):13093-13100
Two‐dimensional (2D) lead‐free halide perovskites have generated enormous perception in the field of optoelectronics due to their fascinating optical properties. However, an in‐depth understanding on their shape‐controlled charge‐carrier recombination dynamics is still lacking, which could be resolved by exploring the photoluminescence (PL) blinking behaviour at the single‐particle level. Herein, we demonstrate, for the first time, the synthesis of nanocrystals (NCs) and 2D nanosheets (NSs) of layered mixed halide, Cs3Bi2I6Cl3, by solution‐based method. We applied fluorescence microscopy and super‐resolution optical imaging at single‐particle level to investigate their morphology‐dependent PL properties. Narrow emission line widths and passivation of non‐radiative defects were evidenced for 2D layered nanostructures, whereas the activation of shallow trap states was recognized at 77 K. Interestingly, individual NCs were found to display temporal intermittency (blinking) in PL emission. On the other hand, NS showed temporal PL intensity fluctuations within localized domains of the crystal. In addition, super‐resolution optical image of the NS from localization‐based method showed spatial inhomogeneity of the PL intensity within perovskite crystal. 相似文献
10.
Norman Pellet Dr. Peng Gao Dr. Giuliano Gregori Dr. Tae‐Youl Yang Dr. Mohammad K. Nazeeruddin Prof. Joachim Maier Prof. Michael Grätzel 《Angewandte Chemie (International ed. in English)》2014,53(12):3151-3157
Hybrid organic–inorganic lead halide perovskite APbX3 pigments, such as methylammonium lead iodide, have recently emerged as excellent light harvesters in solid‐state mesoscopic solar cells. An important target for the further improvement of the performance of perovskite‐based photovoltaics is to extend their optical‐absorption onset further into the red to enhance solar‐light harvesting. Herein, we show that this goal can be reached by using a mixture of formamidinium (HN=CHNH3+, FA) and methylammonium (CH3NH3+, MA) cations in the A position of the APbI3 perovskite structure. This combination leads to an enhanced short‐circuit current and thus superior devices to those based on only CH3NH3+. This concept has not been applied previously in perovskite‐based solar cells. It shows great potential as a versatile tool to tune the structural, electrical, and optoelectronic properties of the light‐harvesting materials. 相似文献
11.
Ion‐Exchange‐Induced 2D–3D Conversion of HMA1−xFAxPbI3Cl Perovskite into a High‐Quality MA1−xFAxPbI3 Perovskite 下载免费PDF全文
Ge Li Taiyang Zhang Nanjie Guo Feng Xu Dr. Xufang Qian Prof. Yixin Zhao 《Angewandte Chemie (International ed. in English)》2016,55(43):13460-13464
High‐quality phase‐pure MA1?xFAxPbI3 planar films (MA=methylammonium, FA=formamidinium) with extended absorption and enhanced thermal stability are difficult to deposit by regular simple solution chemistry approaches owing to crystallization competition between the easy‐to‐crystallize but unwanted δ‐FAPbI3/MAPbI3 and FAxMA1?xPbI3 requiring rigid crystallization conditions. Here A 2D–3D conversion to transform compact 2D mixed composition HMA1?xFAxPbI3Cl perovskite precursor films into 3D MA1?xFAxPbI3 (x=0.1–0.9) perovskites is presented. The designed Cl/I and H/FA(MA) ion exchange reaction induced fast transformation of compact 2D perovskite film, helping to form the phase‐pure and high quality MA1?xFAxPbI3 without δ‐FAPbI3 and MAPbI3 impurity. In all, we successfully developed a facile one‐step method to fabricate high quality phase‐pure MA1?xFAxPbI3 (x=0.1–0.9) perovskite films by 2D–3D conversion of HMA1?xFAxPbI3Cl perovskite. This 2D–3D conversion is a promising strategy for lead halide perovskite fabrication. 相似文献
12.
An Above‐Room‐Temperature Ferroelectric Organo–Metal Halide Perovskite: (3‐Pyrrolinium)(CdCl3) 下载免费PDF全文
Dr. Heng‐Yun Ye Dr. Yi Zhang Dr. Da‐Wei Fu Prof. Ren‐Gen Xiong 《Angewandte Chemie (International ed. in English)》2014,53(42):11242-11247
Hybrid organo–metal halide perovskite materials, such as CH3NH3PbI3, have been shown to be some of the most competitive candidates for absorber materials in photovoltaic (PV) applications. However, their potential has not been completely developed, because a photovoltaic effect with an anomalously large voltage can be achieved only in a ferroelectric phase, while these materials are probably ferroelectric only at temperatures below 180 K. A new hexagonal stacking perovskite‐type complex (3‐pyrrolinium)(CdCl3) exhibits above‐room‐temperature ferroelectricity with a Curie temperature Tc=316 K and a spontaneous polarization Ps=5.1 μC cm?2. The material also exhibits antiparallel 180° domains which are related to the anomalous photovoltaic effect. The open‐circuit photovoltage for a 1 mm‐thick bulky crystal reaches 32 V. This finding could provide a new approach to develop solar cells based on organo–metal halide perovskites in photovoltaic research. 相似文献
13.
Self‐Template‐Directed Synthesis of Porous Perovskite Nanowires at Room Temperature for High‐Performance Visible‐Light Photodetectors 下载免费PDF全文
Sifei Zhuo Jingfang Zhang Yanmei Shi Yi Huang Prof. Dr. Bin Zhang 《Angewandte Chemie (International ed. in English)》2015,54(19):5693-5696
The unique optoelectronic properties and promising photovoltaic applications of organolead halide perovskites have driven the exploration of facile strategies to synthesize organometal halide perovskites and corresponding hybrid materials and devices. Currently, the preparation of CH3NH3PbBr3 perovskite nanowires, especially those with porous features, is still a great challenge. An efficient self‐template‐directed synthesis of high‐quality porous CH3NH3PbBr3 perovskite nanowires in solution at room temperature using the Pb‐containing precursor nanowires as both the sacrificial template and the Pb2+ source in the presence of CH3NH3Br and HBr is now presented. The initial formation of CH3NH3PbBr3 perovskite layers on the surface of the precursor nanowires and the following dissolution of the organic component of the latter led to the formation of mesopores and the preservation of the 1D morphology. Furthermore, the perovskite nanowires are potential materials for visible‐light photodetectors with high sensitivity and stability. 相似文献
14.
Cytotoxicity of Exfoliated Transition‐Metal Dichalcogenides (MoS2, WS2, and WSe2) is Lower Than That of Graphene and its Analogues 下载免费PDF全文
Wei Zhe Teo Elaine Lay Khim Chng Prof. Zdeněk Sofer Prof. Martin Pumera 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(31):9627-9632
Studies involving transition‐metal dichalcogenides (TMDs) have been around for many decades and in recent years, many were focused on using TMDs to synthesize inorganic analogues of carbon nanotubes, fullerene, as well as graphene and its derivatives with the ultimate aim of employing these materials into consumer products. In view of this rising trend, we investigated the cytotoxicity of three common exfoliated TMDs (exTMDs), namely MoS2, WS2, and WSe2, and compared their toxicological effects with graphene oxides and halogenated graphenes to find out whether these inorganic analogues of graphenes and derivatives would show improved biocompatibility. Based on the cell viability assessments using methylthiazolyldiphenyl‐tetrazolium bromide (MTT) and water‐soluble tetrazolium salt (WST‐8) assays on human lung carcinoma epithelial cells (A549) following a 24 h exposure to varying concentrations of the three exTMDs, it was concluded that MoS2 and WS2 nanosheets induced very low cytotoxicity to A549 cells, even at high concentrations. On the other hand, WSe2 exhibited dose‐dependent toxicological effects on A549 cells, reducing cell viability to 31.8 % at the maximum concentration of 400 μg mL?1; the higher cytotoxicity displayed by WSe2 might be linked to the identity of the chalcogen. In comparison with graphene oxides and halogenated graphenes, MoS2 and WS2 were much less hazardous, whereas WSe2 showed similar degree of cytotoxicity. Future in‐depth studies should be built upon this first work on the in vitro cytotoxicity of MoS2 and WS2 to ensure that they do not pose acute toxicity. Lastly, nanomaterial‐induced interference control experiments revealed that exTMDs were capable of reacting with MTT assay viability markers in the absence of cells, but not with WST‐8 assay. This suggests that the MTT assay is not suitable for measuring the cytotoxicity of exTMDs because inflated results will be obtained, giving false impressions that the materials are less toxic. 相似文献
15.
Yuhang Liu Seckin Akin Alexander Hinderhofer Felix T. Eickemeyer Hongwei Zhu Ji‐Youn Seo Jiahuan Zhang Frank Schreiber Hong Zhang Shaik M. Zakeeruddin Anders Hagfeldt M. Ibrahim Dar Michael Grtzel 《Angewandte Chemie (International ed. in English)》2020,59(36):15688-15694
As a result of their attractive optoelectronic properties, metal halide APbI3 perovskites employing formamidinium (FA+) as the A cation are the focus of research. The superior chemical and thermal stability of FA+ cations makes α‐FAPbI3 more suitable for solar‐cell applications than methylammonium lead iodide (MAPbI3). However, its spontaneous conversion into the yellow non‐perovskite phase (δ‐FAPbI3) under ambient conditions poses a serious challenge for practical applications. Herein, we report on the stabilization of the desired α‐FAPbI3 perovskite phase by protecting it with a two‐dimensional (2D) IBA2FAPb2I7 (IBA=iso‐butylammonium overlayer, formed via stepwise annealing. The α‐FAPbI3/IBA2FAPb2I7 based perovskite solar cell (PSC) reached a high power conversion efficiency (PCE) of close to 23 %. In addition, it showed excellent operational stability, retaining around 85 % of its initial efficiency under severe combined heat and light stress, that is, simultaneous exposure with maximum power tracking to full simulated sunlight at 80 °C over 500 h. 相似文献
16.
The crystallographic defects inevitably incur during the solution processed organic‐inorganic hybrid perovskite film, especially at surface and the grain boundaries (GBs) of perovskite film, which can further result in the reduced cell performance and stability of perovskite solar cells (PSCs). Here, a simple defect passivation method was employed by treating perovskite precursor film with a hydrophobic tetra‐ammonium zinc phthalocyanine (ZnPc). The results demonstrated that a 2D‐3D graded perovskite interface with a capping layer of 2D (ZnPc)0.5MAn ? 1PbnI3n + 1 perovskite together with 3D MAPbI3 perovskite was successfully constructed on the top of 3D perovskite layer. This situation realized the efficient GBs passivation, thus reducing the defects in GBs. As expected, the corresponding PSCs with modified perovskite revealed an improved cell performance. The best efficiency reached 19.6%. Especially, the significantly enhanced long‐term stability of the responding PSCs against humidity and heating was remarkably achieved. Such a strategy in this work affords an efficient method to improve the stability of PSCs and thus probably brings the PSCs closer to practical commercialization. 相似文献
17.
Synthesis of Lead‐free CsGeI3 Perovskite Colloidal Nanocrystals and Electron Beam‐induced Transformations 下载免费PDF全文
Xiaotong Wu Weidong Song Dr. Qian Li Xixia Zhao Dr. Dongsheng He Prof. Dr. Zewei Quan 《化学:亚洲杂志》2018,13(13):1654-1659
Colloidal nanocrystals (NCs) of metal halide perovskite have recently aroused great research interest, due to their remarkable optical and electronic properties. We report a solution synthesis of a new member in this category, that is, all‐inorganic lead‐free cesium germanium iodine (CsGeI3) perovskite NCs. These CsGeI3 colloidal NCs are confirmed to adopt a rhombohedral structure. Moreover, the electron beam‐induced transformations of these lead‐free perovskite NCs have been investigated for the first time. The fracture of single‐crystalline CsGeI3 nanocubes occurs first, followed by the emergence and growth of cesium iodine (CsI) single crystals and the final fragmentation into small debris with random orientations. Notably, the electron‐reduced Ge species in CsGeI3 nanocubes exhibit a distinctive transformation path, compared to heavier Pb atoms in lead halide perovskite NCs. 相似文献
18.
Ruiling Zhang Xin Mao Yang Yang Songqiu Yang Wenyuan Zhao Tuerdi Wumaier Donghui Wei Weiqiao Deng Keli Han 《Angewandte Chemie (International ed. in English)》2019,58(9):2725-2729
Lead‐free zero‐dimensional (0D) organic‐inorganic metal halide perovskites have recently attracted increasing attention for their excellent photoluminescence properties and chemical stability. Here, we report the synthesis and characterization of an air‐stable 0D mixed metal halide perovskite (C8NH12)4Bi0.57Sb0.43Br7?H2O, in which individual [BiBr6]3? and [SbBr6]3? octahedral units are completely isolated and surrounded by the large organic cation C8H12N+. Upon photoexcitation, the bulk crystals exhibit ultra‐broadband emission ranging from 400 to 850 nm, which originates from both free excitons and self‐trapped excitons. This is the first example of 0D perovskites with broadband emission spanning the entire visible spectrum. In addition, (C8NH12)4Bi0.57Sb0.43Br7?H2O exhibits excellent humidity and light stability. These findings present a new direction towards the design of environmentally‐friendly, high‐performance 0D perovskite light emitters. 相似文献
19.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(15):4316-4319
Two‐dimensional (2D) organic–inorganic hybrid perovskite nanosheets (NSs) are attracting increasing research interest due to their unique properties and promising applications. Here, for the first time, we report the facile synthesis of single‐ and few‐layer free‐standing phenylethylammonium lead halide perovskite NSs, that is, (PEA)2PbX4 (PEA=C8H9NH3, X=Cl, Br, I). Importantly, their lateral size can be tuned by changing solvents. Moreover, these ultrathin 2D perovskite NSs exhibit highly efficient and tunable photoluminescence, as well as superior stability. Our study provides a simple and general method for the controlled synthesis of 2D perovskite NSs, which may offer a new avenue for their fundamental studies and optoelectronic applications. 相似文献
20.
《Angewandte Chemie (International ed. in English)》2017,56(15):4252-4255
Two‐dimensional (2D) organic–inorganic hybrid perovskite nanosheets (NSs) are attracting increasing research interest due to their unique properties and promising applications. Here, for the first time, we report the facile synthesis of single‐ and few‐layer free‐standing phenylethylammonium lead halide perovskite NSs, that is, (PEA)2PbX4 (PEA=C8H9NH3, X=Cl, Br, I). Importantly, their lateral size can be tuned by changing solvents. Moreover, these ultrathin 2D perovskite NSs exhibit highly efficient and tunable photoluminescence, as well as superior stability. Our study provides a simple and general method for the controlled synthesis of 2D perovskite NSs, which may offer a new avenue for their fundamental studies and optoelectronic applications. 相似文献