共查询到20条相似文献，搜索用时 15 毫秒
1.
Qundong Fu Xiaolei Wang Fucai Liu Yuxin Dong Zirui Liu Shoujun Zheng Apoorva Chaturvedi Jiadong Zhou Peng Hu Zhuqing Zhu Fang Bo Yi Long Zheng Liu 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(39)
Thanks to their unique optical and electric properties, 2D materials have attracted a lot of interest for optoelectronic applications. Here, the emerging 2D materials, organic–inorganic hybrid perovskites with van der Waals interlayer interaction (Ruddlesden–Popper perovskites), are synthesized and characterized. Photodetectors based on the few‐layer Ruddlesden–Popper perovskite show good photoresponsivity as well as good detectivity. In order to further improve the photoresponse performance, 2D MoS2 is chosen to construct the perovskite–MoS2 heterojunction. The performance of the hybrid photodetector is largely improved with 6 and 2 orders of magnitude enhancement for photoresponsivity (104 A W?1) and detectivity (4 × 1010 Jones), respectively, which demonstrates the facile charge separation at the interface between perovskite and MoS2. Furthermore, the contribution of back gate tuning is proved with a greatly reduced dark current. The results demonstrated here will open up a new field for the investigation of 2D perovskites for optoelectronic applications. 相似文献
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Li Na Quan Rafael Quintero‐Bermudez Oleksandr Voznyy Grant Walters Ankit Jain James Zhangming Fan Xueli Zheng Zhenyu Yang Edward H. Sargent 《Advanced materials (Deerfield Beach, Fla.)》2017,29(21)
Perovskite nanocrystals (NCs) have attracted attention due to their high photoluminescence quantum yield (PLQY) in solution; however, maintaining high emission efficiency in the solid state remains a challenge. This study presents a solution‐phase synthesis of efficient green‐emitting perovskite NCs (CsPbBr3) embedded in robust and air‐stable rhombic prism hexabromide (Cs4PbBr6) microcrystals, reaching a PLQY of 90%. Theoretical modeling and experimental characterization suggest that lattice matching between the NCs and the matrix contribute to improved passivation, while spatial confinement enhances the radiative rate of the NCs. In addition, dispersing the NCs in a matrix prevents agglomeration, which explains their high PLQY. 相似文献
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Mojun Chen Jihyuk Yang Zhenyu Wang Zhaoyi Xu Heekwon Lee Hyeonseok Lee Zhiwen Zhou Shien‐Ping Feng Sanghyeon Lee Jaeyeon Pyo Seung Kwon Seol Dong‐Keun Ki Ji Tae Kim 《Advanced materials (Deerfield Beach, Fla.)》2019,31(44)
As competing with the established silicon technology, organic–inorganic metal halide perovskites are continually gaining ground in optoelectronics due to their excellent material properties and low‐cost production. The ability to have control over their shape, as well as composition and crystallinity, is indispensable for practical materialization. Many sophisticated nanofabrication methods have been devised to shape perovskites; however, they are still limited to in‐plane, low‐aspect‐ratio, and simple forms. This is in stark contrast with the demands of modern optoelectronics with freeform circuitry and high integration density. Here, a nanoprecision 3D printing is developed for organic–inorganic metal halide perovskites. The method is based on guiding evaporation‐induced perovskite crystallization in mid‐air using a femtoliter ink meniscus formed on a nanopipette, resulting in freestanding 3D perovskite nanostructures with a preferred crystal orientation. Stretching the ink meniscus with a pulling process enables on‐demand control of the nanostructure's diameter and hollowness, leading to an unprecedented tubular‐solid transition. With varying the pulling direction, a layer‐by‐layer stacking of perovskite nanostructures is successfully demonstrated with programmed shapes and positions, a primary step for additive manufacturing. It is expected that the method has the potential to create freeform perovskite nanostructures for customized optoelectronics. 相似文献
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In0.53Ga0.47As PIN光电探测器的温度特性分析 总被引：3，自引：0，他引：3
从理论和实验上分析了双异质结In0.53Ga0.47As PIN光电探测器在不同的反向偏置电压下暗电流在甚宽温度范围内的温度特性。结果表明：在反向偏置低压与高压段,产生一复合电流与隧道电流(缺陷隧道电流与带带间隧道电流)分别占主导地位,并呈现出相应的温度特性。还从理论与实验两方面探讨了噪声对探测器R0A的影响,结果表明：在低温段,产生一复合噪声起主要作用,在高温段,俄歇复合噪声起主要作用。 相似文献
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Xiaoli Zhang He Liu Weigao Wang Jinbao Zhang Bing Xu Ke Lin Karen Yuanjin Zheng Sheng Liu Shuming Chen Kai Wang Xiao Wei Sun 《Advanced materials (Deerfield Beach, Fla.)》2017,29(18)
Organic–inorganic hybrid perovskite materials with mixed cations have demonstrated tremendous advances in photovoltaics recently, by showing a significant enhancement of power conversion efficiency and improved perovskite stability. Inspired by this development, this study presents the facile synthesis of mixed‐cation perovskite nanocrystals based on FA(1?x )Csx PbBr3 (FA = CH(NH2)2). By detailed characterization of their morphological, optical, and physicochemical properties, it is found that the emission property of the perovskite, FA(1?x )Csx PbBr3, is significantly dependent on the substitution content of the Cs cations in the perovskite composition. These mixed‐cation perovskites are employed as light emitters in light‐emitting diodes (LEDs). With an optimized composition of FA0.8Cs0.2PbBr3, the LEDs exhibit encouraging performance with a highest reported luminance of 55 005 cd m?2 and a current efficiency of 10.09 cd A?1. This work provides important instructions on the future compositional optimization of mixed‐cation perovskite for obtaining high‐performance LEDs. The authors believe this work is a new milestone in the development of bright and efficient perovskite LEDs. 相似文献
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Ryosuke Nishikubo Norimitsu Tohnai Ichiro Hisaki Akinori Saeki 《Advanced materials (Deerfield Beach, Fla.)》2017,29(23)
Lead halide perovskites have shown much promise for high‐performing solar cells due to their inherent electronic nature, and though the color of bright‐light emitters based on perovskite nanoparticles can be tuned by halide mixing and/or size control, dynamic switching using external stimuli remains a challenge. This article reports an unprecedented lower critical solution temperature (LCST) for toluene solutions containing methylammonium lead bromide (MAPbBr3), oleic acid, alkylamines, and dimethylformamide. The delicate interplay of these molecules and ions allows for the reversible formation and decomposition of MAPbBr3 nanoparticles upon heating and cooling, which is accompanied by green and blue photoemissions at each state. An intermediate 1D crystal with PbBr2‐amine coordination is found to play pivotal role in this, and a mechanistic insight is provided based on a three‐state model. In addition to a high quantum yield (up to 85%), this system allows for control over the cloud point (30?80 °C) through compositional engineering and the luminescent color (blue to red) via halogen exchange, thus making it a versatile solution for developing functional molecular organic–inorganic LCST quantum dots. 相似文献
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Perovskite Nanoparticles: Thermoresponsive Emission Switching via Lower Critical Solution Temperature Behavior of Organic–Inorganic Perovskite Nanoparticles (Adv. Mater. 23/2017) 
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下载免费PDF全文 Ryosuke Nishikubo Norimitsu Tohnai Ichiro Hisaki Akinori Saeki 《Advanced materials (Deerfield Beach, Fla.)》2017,29(23)
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《Small Methods》2018,2(1)
To meet the increasing energy demands of the growing society, environmentally friendly and renewable energy sources are needed. Organic–inorganic halide perovskites are a promising class of materials for building solar cells due to their easy fabrication, flexibility, and bandgap tunability. The highest efficiency achieved with these materials in the lab is comparable to conventional silicon solar cells currently on the market. However, their commercialization is hampered by certain challenges, such as stability, lead toxicity, and reproducibility. Inhomogeneities in the perovskite material at the atomic scale are identified as a possible cause of these issues. To study this further, scanning probe microscopy offer a unique real‐space visualization of the sample topography down to the atomic level. Simultaneously, the sample morphology can be correlated to its electronic, chemical, and optoelectronic properties. Here, the latest studies on organic–inorganic halide perovskites using scanning probe microscopy methods such as atomic force microscopy, scanning tunneling microscopy, and scanning near field optical microscopy are reviewed. A comparison of each technique and their specific use in the field of perovskite photovoltaics is provided. Particular focus is given to unraveling specific properties that are relevant for a fundamental understanding of perovskite materials and solar cells. 相似文献
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Memory Devices: Resistive Switching Behavior in Organic–Inorganic Hybrid CH3NH3PbI3−xClx Perovskite for Resistive Random Access Memory Devices (Adv. Mater. 40/2015) 下载免费PDF全文
下载免费PDF全文 Eun Ji Yoo Miaoqiang Lyu Jung‐Ho Yun Chi Jung Kang Young Jin Choi Lianzhou Wang 《Advanced materials (Deerfield Beach, Fla.)》2015,27(40):6303-6303
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Manukumara Manjappa Yogesh Kumar Srivastava Ankur Solanki Abhishek Kumar Tze Chien Sum Ranjan Singh 《Advanced materials (Deerfield Beach, Fla.)》2017,29(32)
The recent meteoric rise in the field of photovoltaics with the discovery of highly efficient solar‐cell devices is inspired by solution‐processed organic–inorganic lead halide perovskites that exhibit unprecedented light‐to‐electricity conversion efficiencies. The stunning performance of perovskites is attributed to their strong photoresponsive properties that are thoroughly utilized in designing excellent perovskite solar cells, light‐emitting diodes, infrared lasers, and ultrafast photodetectors. However, optoelectronic application of halide perovskites in realizing highly efficient subwavelength photonic devices has remained a challenge. Here, the remarkable photoconductivity of organic–inorganic lead halide perovskites is exploited to demonstrate a hybrid perovskite–metamaterial device that shows extremely low power photoswitching of the metamaterial resonances in the terahertz part of the electromagnetic spectrum. Furthermore, a signature of a coupled phonon–metamaterial resonance is observed at higher pump powers, where the Fano resonance amplitude is extremely weak. In addition, a low threshold, dynamic control of the highly confined electric field intensity is also observed in the system, which could tremendously benefit the new generation of subwavelength photonic devices as active sensors, low threshold optically controlled lasers, and active nonlinear devices with enhanced functionalities in the infrared, optical, and the terahertz parts of the electromagnetic spectrum. 相似文献
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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
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Organic–inorganic perovskite materials have mobile charged point defects that migrate in response to voltage biasing and illumination, causing device performance variation over time. Improvements in device stability and reliability require methods to visualize point defect migration, estimate ionic mobilities, and identify factors influencing their migration. In this work, a versatile method is demonstrated to track nonradiative point defect migration in situ. Photoluminescence mapping of laterally biased perovskite films is used to track continuous changes in nonradiative recombination as charge‐trapping defects migrate between the device electrodes. A Monte Carlo framework of defect drift and diffusion is developed that is consistent with experimental photoluminescence observations, which combined enables point defect mobility estimation in methylammonium lead iodide films. Furthermore, measurements performed on materials with varied grain sizes demonstrate that point defect mobility is 1500× faster at grain boundaries compared to bulk. These findings imply that grain morphology can be used to tune point defect mobility such that large‐grained or single‐crystal materials inhibit point defect migration. The methods used in this work can be applied to visualize and quantify the migration of charge‐trapping point defects in a wide range of state‐of‐the‐art perovskite materials targeted toward reduced ionic mobilities and superior device stability. 相似文献
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Jingying Wang Chuang Zhang Haoliang Liu Xiaojie Liu Hangwen Guo Dali Sun Zeev Valy Vardeny 《Advanced materials (Deerfield Beach, Fla.)》2019,31(41)
The hybrid organic–inorganic perovskites (HOIPs) form a new class of semiconductors which show promising optoelectronic device applications. Remarkably, the optoelectronic properties of HOIP are tunable by changing the chemical components of their building blocks. Recently, the HOIP spintronic properties and their applications in spintronic devices have attracted substantial interest. Here the impact of the chemical component diversity in HOIPs on their spintronic properties is studied. Spin valve devices based on HOIPs with different organic cations and halogen atoms are fabricated. The spin diffusion length is obtained in the various HOIPs by measuring the giant magnetoresistance (GMR) response in spin valve devices with different perovskite interlayer thicknesses. In addition spin lifetime is also measured from the Hanle response. It is found that the spintronic properties of HOIPs are mainly determined by the halogen atoms, rather than the organic cations. The study provides a clear avenue for engineering spintronic devices based on HOIPs. 相似文献
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Yanyun Ren Hanlu Ma Wei Wang Zhongqiang Wang Haiyang Xu Xiaoning Zhao Weizhen Liu Jiangang Ma Yichun Liu 《Advanced Materials Technologies》2019,4(1)
As one key issue of resistive switching (RS) memory, the cycling endurance is poorly understood in hybrid perovskite‐based memory devices. Here, the cycling failure and the corresponding cycling‐induced degradation of CH3NH3PbI3‐based resistive random access memory devices are discussed. The high resistance state clearly decreases with the number of operation cycles, finally triggering irreversible failure in the collapse of switching window. By monitoring the I–V curves for all cycles, a negative set event is observed to be the critical turning point that considerably accelerates the cycling degradation rate. The decrease of |Vset| and |Vreset| indicates a reduction of the migration barrier of iodine vacancies (VI), which accounts for the appearance of a negative set after cycling. The understanding of RS cycling degradation can promote the optimization of device endurance by slowing the defect accumulation rate. 相似文献
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Peng Wang Yang Wang Lei Ye Mingzai Wu Runzhang Xie Xudong Wang Xiaoshuang Chen Zhiyong Fan Jianlu Wang Weida Hu 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(22)
Zinc oxide (ZnO) nanosheets have demonstrated outstanding electrical and optical properties, which are well suited for ultraviolet (UV) photodetectors. However, they have a high density of intrinsically unfilled traps, and it is difficult to achieve p‐type doping, leading to the poor performance for low light level switching ratio and a high dark current that limit practical applications in UV photodetection. Here, UV photodetectors based on ZnO nanosheets are demonstrated, whose performance is significantly improved by using a ferroelectric localized field. Specifically, the photodetectors have achieved a responsivity of up to 3.8 × 105 A W?1, a detectivity of 4.4 × 1015 Jones, and a photocurrent gain up to 1.24 × 106. These device figures of merit are far beyond those of traditional ZnO ultraviolet photodetectors. In addition, the devices' initial dark current can be easily restored after continuous photocurrent measurement by using a positive gate voltage pulse. This study establishes a new approach to produce high‐sensitivity and low‐dark‐current ultraviolet photodetectors and presents a crucial step for further practical applications. 相似文献