共查询到20条相似文献,搜索用时 15 毫秒
1.
Meiying Leng Zhengwu Chen Ying Yang Zha Li Kai Zeng Kanghua Li Guangda Niu Yisu He Qingchao Zhou Jiang Tang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(48):15236-15240
Lead halide perovskite quantum dots (QDs) are promising candidates for future lighting applications, due to their high quantum yield, narrow full width at half maximum (FWHM), and wide color gamut. However, the toxicity of lead represents a potential obstacle to their utilization. Although tin(II) has been used to replace lead in films and QDs, the high intrinsic defect density and oxidation vulnerability typically leads to unsatisfactory material properties. Bismuth, with much lower toxicity than lead, is promising to constitute lead‐free perovskite materials because Bi3+ is isoelectronic to Pb2+ and more stable than Sn2+. Herein we report, for the first time, the synthesis and optical characterization of MA3Bi2Br9 perovskite QDs with photoluminescence quantum yield (PLQY) up to 12 %, which is much higher than Sn‐based perovskite nanocrystals. Furthermore, the photoluminescence (PL) peaks of MA3Bi2X9 QDs could be easily tuned from 360 to 540 nm through anion exchange. 相似文献
2.
Meiying Leng Zhengwu Chen Ying Yang Dr. Zha Li Kai Zeng Kanghua Li Dr. Guangda Niu Yisu He Qingchao Zhou Prof. Jiang Tang 《Angewandte Chemie (International ed. in English)》2016,55(48):15012-15016
Lead halide perovskite quantum dots (QDs) are promising candidates for future lighting applications, due to their high quantum yield, narrow full width at half maximum (FWHM), and wide color gamut. However, the toxicity of lead represents a potential obstacle to their utilization. Although tin(II) has been used to replace lead in films and QDs, the high intrinsic defect density and oxidation vulnerability typically leads to unsatisfactory material properties. Bismuth, with much lower toxicity than lead, is promising to constitute lead‐free perovskite materials because Bi3+ is isoelectronic to Pb2+ and more stable than Sn2+. Herein we report, for the first time, the synthesis and optical characterization of MA3Bi2Br9 perovskite QDs with photoluminescence quantum yield (PLQY) up to 12 %, which is much higher than Sn‐based perovskite nanocrystals. Furthermore, the photoluminescence (PL) peaks of MA3Bi2X9 QDs could be easily tuned from 360 to 540 nm through anion exchange. 相似文献
3.
Dr. Jialong Duan Dr. Yuanyuan Zhao Prof. Benlin He Prof. Qunwei Tang 《Angewandte Chemie (International ed. in English)》2018,57(14):3787-3791
All‐inorganic perovskite solar cells with high efficiency and improved stability are promising for commercialization. A multistep solution‐processing method was developed to fabricate high‐purity inorganic CsPbBr3 perovskite films for use in efficient solar cells. By tuning the number of deposition cycles (n) of a CsBr solution, the phase conversion from CsPb2Br5 (n ≤3), to CsPbBr3 (n=4), and Cs4PbBr6 (n≥5) was optimized to achieve vertical‐ and monolayer‐aligned grains. Upon interfacial modification with graphene quantum dots, the all‐inorganic perovskite solar cell (without a hole‐transporting layer) achieved a power conversion efficiency (PCE) as high as 9.72 % under standard solar illumination conditions. Under challenging conditions, such as 90 % relative humidity (RH) at 25 °C or 80 °C at zero humidity, the optimized device retained 87 % PCE over 130 days or 95 % over 40 days, compared to the initial efficiency. 相似文献
4.
Amino‐Assisted Anchoring of CsPbBr3 Perovskite Quantum Dots on Porous g‐C3N4 for Enhanced Photocatalytic CO2 Reduction 下载免费PDF全文
Man Ou Dr. Wenguang Tu Dr. Shengming Yin Weinan Xing Shuyang Wu Haojing Wang Shipeng Wan Prof. Dr. Qin Zhong Prof. Dr. Rong Xu 《Angewandte Chemie (International ed. in English)》2018,57(41):13570-13574
Halide perovskite quantum dots (QDs) have great potential in photocatalytic applications if their low charge transportation efficiency and chemical instability can be overcome. To circumvent these obstacles, we anchored CsPbBr3 QDs (CPB) on NHx‐rich porous g‐C3N4 nanosheets (PCN) to construct the composite photocatalysts via N?Br chemical bonding. The 20 CPB‐PCN (20 wt % of QDs) photocatalyst exhibits good stability and an outstanding yield of 149 μmol h?1 g?1 in acetonitrile/water for photocatalytic reduction of CO2 to CO under visible light irradiation, which is around 15 times higher than that of CsPbBr3 QDs. This study opens up new possibilities of using halide perovskite QDs for photocatalytic application. 相似文献
5.
Large‐Scale Synthesis of Highly Luminescent Perovskite‐Related CsPb2Br5 Nanoplatelets and Their Fast Anion Exchange 下载免费PDF全文
Kun‐Hua Wang Liang Wu Lei Li Prof. Dr. Hong‐Bin Yao Prof. Dr. Hai‐Sheng Qian Prof. Dr. Shu‐Hong Yu 《Angewandte Chemie (International ed. in English)》2016,55(29):8328-8332
All‐inorganic cesium lead‐halide perovskite nanocrystals have emerged as attractive optoelectronic nanomaterials owing to their stabilities and highly efficient photoluminescence. Herein we report a new type of highly luminescent perovskite‐related CsPb2Br5 nanoplatelets synthesized by a facile precipitation reaction. The layered crystal structure of CsPb2Br5 promoted an anisotropic two‐dimensional (2D) crystal growth during the precipitation process, thus enabling the large‐scale synthesis of CsPb2Br5 nanoplatelets. Fast anion exchange has also been demonstrated in as‐synthesized CsPb2Br5 nanoplatelets to extend their photoluminescence spectra to the entire visible spectral region. The large‐scale synthesis and optical tunability of CsPb2Br5 nanoplatelets will be advantageous in future applications of optoelectronic devices. 相似文献
6.
Feng Liu Junke Jiang Yaohong Zhang Chao Ding Taro Toyoda Shuzi Hayase Ruixiang Wang Shuxia Tao Qing Shen 《Angewandte Chemie (International ed. in English)》2020,59(22):8421-8424
Phase‐stable CsSnxPb1?xI3 perovskite quantum dots (QDs) hold great promise for optoelectronic applications owing to their strong response in the near‐infrared region. Unfortunately, optimal utilization of their potential is limited by the severe photoluminescence (PL) quenching, leading to extremely low quantum yields (QYs) of approximately 0.3 %. The ultra‐low sodium (Na) doping presented herein is found to be effective in improving PL QYs of these alloyed QDs without alerting their favourable electronic structure. X‐ray photoelectron spectroscopy (XPS) studies suggest the formation of a stronger chemical interaction between I? and Sn2+ ions upon Na doping, which potentially helps to stabilize Sn2+ and suppresses the formation of I vacancy defects. The optimized PL QY of the Na‐doped QDs reaches up to around 28 %, almost two orders of magnitude enhancement compared with the pristine one. 相似文献
7.
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
8.
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
9.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(28):8246-8250
We successfully prepared QDs incorporated into a silica/alumina monolith (QDs‐SAM) by a simple sol–gel reaction of an Al–Si single precursor with CsPbBr3 QDs blended in toluene solution, without adding water and catalyst. The resultant transparent monolith exhibits high photoluminescence quantum yields (PLQY) up to 90 %, and good photostability under strong illumination of blue light for 300 h. We show that the preliminary ligand exchange of didodecyl dimethyl ammonium bromide (DDAB) was very important to protect CsPbBr3 QDs from surface damages during the sol–gel reaction, which not only allowed us to maintain the original optical properties of CsPbBr3 QDs but also prevented the aggregation of QDs and made the monolith transparent. The CsPbBr3 QDs‐SAM in powder form was easily mixed into the resins and applied as color‐converting layer with curing on blue light‐emitting diodes (LED). The material showed a high luminous efficacy of 80 lm W−1 and a narrow emission with a full width at half maximum (FWHM) of 25 nm. 相似文献
10.
Dr. Feng Liu Junke Jiang Dr. Yaohong Zhang Dr. Chao Ding Prof. Taro Toyoda Prof. Shuzi Hayase Prof. Ruixiang Wang Prof. Shuxia Tao Prof. Qing Shen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(22):8499-8502
Phase-stable CsSnxPb1−xI3 perovskite quantum dots (QDs) hold great promise for optoelectronic applications owing to their strong response in the near-infrared region. Unfortunately, optimal utilization of their potential is limited by the severe photoluminescence (PL) quenching, leading to extremely low quantum yields (QYs) of approximately 0.3 %. The ultra-low sodium (Na) doping presented herein is found to be effective in improving PL QYs of these alloyed QDs without alerting their favourable electronic structure. X-ray photoelectron spectroscopy (XPS) studies suggest the formation of a stronger chemical interaction between I− and Sn2+ ions upon Na doping, which potentially helps to stabilize Sn2+ and suppresses the formation of I vacancy defects. The optimized PL QY of the Na-doped QDs reaches up to around 28 %, almost two orders of magnitude enhancement compared with the pristine one. 相似文献
11.
Dr. Peng Gao Dr. Zihao Cui Dr. Xiaolei Liu Dr. Yaqiang Wu Dr. Qianqian Zhang Prof. Zeyan Wang Prof. Zhaoke Zheng Prof. Hefeng Cheng Prof. Yuanyuan Liu Prof. Qing Li Prof. Baibiao Huang Prof. Peng Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(50):e202201095
Lead halide perovskite has triggered a lot of research due to its superior optical properties. However, halide perovskite materials have poor environmental stabilities and are easily affected by external factors such as water and heat, resulting in structural decomposition and performance failure. Contrary to this commonplace concept, it is found that CsPbBr3 (CPB) can convert to CsPb2Br5 (CP2B5) partially when meeting a small amount of water, and the CsPbBr3@CsPb2Br5 (CPB@CP2B5) composite is synthesized by an in situ method accordingly. The CPB@CP2B5 composite shows an enhanced catalytic performance compared with pure CPB, as well as a dramatically synergistic effect of photo and thermal for catalytic CO2 hydrogenation. The CO production rate of CPB@CP2B5 is determined as 69 μmol g−1 h−1 under light irradiation at 200 °C, which is 156.8 and 43.4 times higher than that under pure photo (0.44 μmol g−1 h −1) and pure thermal (1.59 μmol g−1 h −1) condition, respectively. Meanwhile, the CPB@CP2B5 sample is also stable, which shows no significant decline in the catalytic activity during 8 cycles of repeated experiments. The probable mechanism is explored by utilizing a series of in situ characterizations. 相似文献
12.
Dr. Xiaoyu Zhang Prof. Xue Bai Hua Wu Xiangtong Zhang Chun Sun Prof. Yu Zhang Prof. Wei Zhang Prof. Weitao Zheng Prof. William W. Yu Prof. Andrey L. Rogach 《Angewandte Chemie (International ed. in English)》2018,57(13):3337-3342
Lead‐halide perovskites are well known to decompose rapidly when exposed to polar solvents, such as water. Contrary to this common‐place observation, we have found that through introducing a suitable minor amount of water into the reaction mixture, we can synthesize stable CsPbBr3 nanocrystals. The size and the crystallinity, and as a result the band gap tunability of the strongly emitting CsPbBr3 nanocrystals correlate with the water content. Suitable amounts of water change the crystallization environment, inducing the formation of differently shaped perovskites, namely spherical NCs, rectangular nanoplatelets, or nanowires. Bright CsPbBr3 nanocrystals with the photoluminescence quantum yield reaching 90 % were employed for fabrication of inverted hybrid inorganic/organic light‐emitting devices, with the peak luminance of 4428 cd m?2 and external quantum yield of 1.7 %. 相似文献
13.
Mengqi Zhang Dr. Chenghao Bi Yuexing Xia Dr. Xuejiao Sun Xingyu Wang Aqiang Liu Shuyu Tian Prof. Xinfeng Liu Prof. Nora H. de Leeuw Prof. Jianjun Tian 《Angewandte Chemie (International ed. in English)》2023,62(12):e202300149
Perovskite colloidal quantum wells (QWs) are promising to realize narrow deep-blue emission, but the poor optical performance and stability suppress their practical application. Here, we creatively propose a water-driven synthesis strategy to obtain size-homogenized and strongly confined deep-blue CsPbBr3 QWs, corresponding to three monolayers, which emit at the deep-blue wavelength of 456 nm. The water controls the orientation and distribution of the ligands on the surface of the nanocrystals, thus inducing orientated growth through the Ostwald ripening process by phagocytizing unstable nanocrystals to form well-crystallized QWs. These QWs present remarkable stability and high photoluminescence quantum yield of 94 %. Furthermore, we have prepared light-emitting diodes based on the QWs via the all-solution fabrication strategy, achieving an external quantum efficiency of 1 % and luminance of 2946 cd m−2, demonstrating state-of-the-art brightness for perovskite QW-based LEDs. 相似文献
14.
Viktoriia Morad Dr. Michael Wörle Dr. Sergii Yakunin Dr. Gabriele Rainò Olga Nazarenko Markus Fischer Dr. Ivan Infante Prof. Dr. Maksym V. Kovalenko 《Angewandte Chemie (International ed. in English)》2018,57(35):11329-11333
The spatial localization of charge carriers to promote the formation of bound excitons and concomitantly enhance radiative recombination has long been a goal for luminescent semiconductors. Zero‐dimensional materials structurally impose carrier localization and result in the formation of localized Frenkel excitons. Now the fully inorganic, perovskite‐derived zero‐dimensional SnII material Cs4SnBr6 is presented that exhibits room‐temperature broad‐band photoluminescence centered at 540 nm with a quantum yield (QY) of 15±5 %. A series of analogous compositions following the general formula Cs4?xAxSn(Br1?yIy)6 (A=Rb, K; x≤1, y≤1) can be prepared. The emission of these materials ranges from 500 nm to 620 nm with the possibility to compositionally tune the Stokes shift and the self‐trapped exciton emission bands. 相似文献
15.
Red Phosphorescent Bis‐Cyclometalated Iridium Complexes with Fluorine‐, Phenyl‐, and Fluorophenyl‐Substituted 2‐Arylquinoline Ligands 下载免费PDF全文
Jwajin Kim Dr. Kum Hee Lee Dr. Seok Jae Lee Dr. Ho Won Lee Prof. Young Kwan Kim Prof. Young Sik Kim Prof. Seung Soo Yoon 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(12):4036-4045
Red phosphorescent iridium(III) complexes based on fluorine‐, phenyl‐, and fluorophenyl‐substituted 2‐arylquinoline ligands were designed and synthesized. To investigate their electrophosphorescent properties, devices were fabricated with the following structure: indium tin oxide (ITO)/4,4′,4′′‐tris[2‐naphthyl(phenyl)amino]triphenylamine (2‐TNATA)/4,4′‐bis[N‐(1‐naphthyl)‐N‐phenylamino]biphenyl (NPB)/4,4′‐bis(N‐carbazolyl)‐1,1′‐biphenyl (CBP): 8 % iridium (III) complexes/bathocuproine (BCP)/tris(8‐hydroxyquinolinato)aluminum (Alq3)/8‐hydroxyquinoline lithium (Liq)/Al. All devices, which use these materials showed efficient red emissions. In particular, a device exhibited a saturated red emission with a maximum luminance, external quantum efficiency, and luminous efficiency of 14200 cd m?2, 8.44 %, and 6.58 cd A?1 at 20 mA cm?2, respectively. The CIE (x, y) coordinates of this device are (0.67, 0.33) at 12.0 V. 相似文献
16.
Hongbo Li Xiangdong Liu Qifei Ying Chao Wang Wei Jia Xing Xing Lisha Yin Zhenda Lu Kun Zhang Yue Pan Zhan Shi Ling Huang Dianzeng Jia 《Angewandte Chemie (International ed. in English)》2020,59(39):17207-17213
Herein, we report the facile growth of three‐dimensional CsPbBr3 perovskite supercrystals (PSCs) self‐assembled from individual CsPbBr3 perovskite quantum dots (PQDs). By varying the carbon chain length of a surface‐bound ligand molecule, 1‐alkynyl acid, different morphologies of PSCs were obtained accompanied by an over 1000‐fold photoluminescence improvement compared with that of PQDs. Systematic analyses have shown, for the first time, that under UV irradiation, CsBr, the byproduct formed during PQDs synthesis, could effectively catalyze the homocoupling reaction between two alkynyl groups, which further worked as a driving force to push forward the self‐assembly of PQDs. 相似文献
17.
Tian Wu Junnan Li Yatao Zou Hao Xu Kaichuan Wen Shanshan Wan Prof. Dr. Sai Bai Prof. Dr. Tao Song Dr. John A. McLeod Prof. Dr. Steffen Duhm Prof. Dr. Feng Gao Prof. Dr. Baoquan Sun 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(10):4128-4134
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
18.
Xiaoya Yu Linzhong Wu Di Yang Muhan Cao Xing Fan Haiping Lin Qixuan Zhong Yong Xu Qiao Zhang 《Angewandte Chemie (International ed. in English)》2020,59(34):14527-14532
Hydrochromic materials that can reversibly change color upon water treatment have attracted much attention owing to their potential applications in diverse fields. Herein, for the first time, we report that space‐confined CsPbBr3 nanocrystals (NCs) are hydrochromic. When CsPbBr3 NCs are loaded into a porous matrix, reversible transition between luminescent CsPbBr3 and non‐luminescent CsPb2Br5 can be achieved upon the exposure/removal of water. The potential applications of hydrochromic CsPbBr3 NCs in anti‐counterfeiting are demonstrated by using CsPbBr3 NCs@mesoporous silica nanospheres (around 100 nm) as the starting material. Owing to the small particle size and negatively charged surface, the as‐prepared particles can be laser‐jet printed with high precision and high speed. We demonstrate the excellent stability over repeated transformation cycles without color fade. This new discovery may not only deepen the understanding of CsPbX3, but also open a new way to design CsPbX3 materials for new applications. 相似文献
19.
Photoluminescence Quenching in Self‐Assembled CsPbBr3 Quantum Dots on Few‐Layer Black Phosphorus Sheets 下载免费PDF全文
Dr. Subas Muduli Padmini Pandey Gayathri Devatha Rohit Babar Thripuranthaka M Prof. Dushyant C. Kothari Prof. Mukul Kabir Prof. Pramod P. Pillai Prof. Satishchandra Ogale 《Angewandte Chemie (International ed. in English)》2018,57(26):7682-7686
An ordered self‐assembly of CsPbBr3 quantum dots (QDs) was generated on the surface of few‐layer black phosphorus (FLBP). Strong quenching of the QD fluorescence was observed, and analyzed by time‐resolved photoluminescence (TR‐PL) studies, DFT calculations, and photoconductivity measurements. Charge transfer by type I band alignment is suggested to be the cause of the observed effects. 相似文献
20.
Jun Pan Xiyan Li Xiwen Gong Jun Yin Dianli Zhou Lutfan Sinatra Renwu Huang Jiakai Liu Jie Chen Ibrahim Dursun Ahmed M. El‐Zohry Makhsud I. Saidaminov Hong‐Tao Sun Omar F. Mohammed Changhui Ye Edward H. Sargent Osman M. Bakr 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(45):16223-16227
Interest has been growing in defects of halide perovskites in view of their intimate connection with key material optoelectronic properties. In perovskite quantum dots (PQDs), the influence of defects is even more apparent than in their bulk counterparts. By combining experiment and theory, we report herein a halide‐vacancy‐driven, ligand‐directed self‐assembly process of CsPbBr3 PQDs. With the assistance of oleic acid and didodecyldimethylammonium sulfide, surface‐Br‐vacancy‐rich CsPbBr3 PQDs self‐assemble into nanowires (NWs) that are 20–60 nm in width and several millimeters in length. The NWs exhibit a sharp photoluminescence profile (≈18 nm full‐width at‐half‐maximum) that peaks at 525 nm. Our findings provide insight into the defect‐correlated dynamics of PQDs and defect‐assisted fabrication of perovskite materials and devices. 相似文献