Query: Properties and potential optoelectronic applications of lead halide perovskite nanocrystals

Candidate papers:

abstract: Semiconducting lead halide perovskites (LHPs) have not only become prominent thin film absorber materials in photovoltaics but have also proven to be disruptive in the field of colloidal semiconductor nanocrystals (NCs) The most important feature of LHP NCs is their so called defect tolerance the apparently benign nature of structural defects, highly abundant in these compounds, with respect to optical and electronic properties. Here, we review the important differences that exist in the chemistry and physics of LHP NCs as compared with more conventional, tetrahedrally bonded, elemental, and binary semiconductor NCs (such as silicon, germanium, cadmium selenide, gallium arsenide, and indium phosphide) We survey the prospects of LHP NCs for optoelectronic applications such as in television displays, light emitting devices, and solar cells, emphasizing the practical hurdles that remain to be overcome.
author_names: Maksym V Kovalenko

Loredana Protesescu

Maryna I Bodnarchuk
title: Properties and potential optoelectronic applications of lead halide perovskite nanocrystals
venue: Science
year: 2017

abstract: Abstract Cesium lead halide perovskite nanocrystals (NCs) have emerged as a key material for optoelectronic applications owing to their outstanding optical properties and easy synthesis in solution. Nowadays, the scientific community is facing a daring challenge toward the synthesis of lead free perovskite NCs with high stability and excellent optical properties for the fabrication of optoelectronic devices with enhanced performance. In this sense, cesium lead free halide perovskites (CsLFHPs) are demonstrated as extremely less susceptible toward oxygen and moisture and suitable candidates for long term device applications. Thus, synthesis and identification of CsLFHP NCs essentially need understanding of surface chemistry to improve their structural and optical properties. Recent experimental findings on synthesis and properties of CsLFHP nanomaterials emphasizing that the chelation effect of organic ligands on the surface of perovskite NCs have to be thoroughly examined to improve their properties. This chapter summarizes recent advances that have been made in synthesis and surface chemistry of CsLFHP nanomaterials. The crucial role of solvents and organic ligands in synthesizing different morphologies of CsLFHP NCs are evaluated. Important experimental observations that are different from the already demonstrated cesium lead halide perovskite nanomaterials are outlined. Further suggestions in improving the surface properties of CsLFHP nanomaterials and their potential applications in several areas are also discussed.
author_names: Ananthakumar Soosaimanickam

Pedro J rodriguez-Canto

Juan P Martinez-Pastor

Rafael Abargues
title: Recent advances in synthesis, surface chemistry of cesium lead free halide perovskite nanocrystals and their potential applications
year: 2020

abstract: Lead (Pb halide perovskite nanocrystals (NCs) are interesting nanomaterials due to their excellent optical properties, such as narrow band emission, high photoluminescence (PL) efficiency, and wide color gamut. However, these NCs have several critical problems, such as the high toxicity of Pb, its tendency to accumulate in the human body, and phase instability. Although Pb free metal (Bi, Sn, etc. halide perovskite NCs have recently been reported as possible alternatives, they exhibit poor optical and electrical properties as well as abundant intrinsic defect sites. For the first time, the synthesis and optical characterization of cesium ytterbium triiodide (CsYbI3 cubic perovskite NCs with highly uniform size distribution and high crystallinity using a simple hot injection method are reported. Strong excitation independent emission and high quantum yields for the prepared NCs are verified using photoluminescence measurements. Furthermore, these CsYbI3 NCs exhibit potential for use in organic inorganic hybrid photodetectors as a photoactive layer. The as prepared samples exhibit clear on off switching behavior as well as high photoresponsivity (2.4 x 103 A W 1 and external quantum efficiency (EQE, 5.8 x 105 due to effective exciton dissociation and charge transport. These results suggest that CsYbI3 NCs offer tremendous opportunities in electronic and optoelectronic applications, such as chemical sensors, light emitting diodes (LEDs) and energy conversion and storage devices.
author_names: Byung Joon Moon

Sang Jin Kim

Seungmin Lee

Aram Lee

Hyunjung Lee

Dong Su Lee

Tae-Wook Kim

Seoung-Ki Lee

Sukang Bae

Sang Hyun Lee
title: Rare Earth Element Ytterbium Substituted Lead Free Inorganic Perovskite Nanocrystals for Optoelectronic Applications.
venue: Advanced materials
year: 2019

abstract: Lead halide perovskite nanocrystals (NCs) have been widely investigated owing to their potential applications as optoelectronic devices. However, these materials suffer from poor water stability, which make them impossible to be applied in biomedicine. Here, insoluble CsPbBr3/CsPb2Br5 composite NCs were successfully synthesized via simple water assisted chemical transformation of perovskite NCs. Water plays two key roles in this synthesis: (i) stripping CsBr from CsPbBr3/Cs4PbBr6 and (ii) modifying the coordination number of Pb2+ (six in CsPbBr3 and Cs4PbBr6 vs eight in CsPb2Br5) The as prepared CsPbBr3/CsPb2Br5 composite NCs not only retain the photoluminescence quantum yield (up to 80% and a narrow full width to half maximum of 16 nm, but also present excellent water stability and low cytotoxicity. With these properties, the CsPbBr3/CsPb2Br5 composite NCs were demonstrated as efficient fluorescent probes in live HeLa cells. We believe that our finding not only provides a new method to prepare insoluble, narrow band, and brightly luminescent CsPbBr3/CsPb2Br5 composite NCs, but also extend the potential applications of lead halides in biomedicine.
author_names: Sunqi Lou

Zhi Zhou

Tongtong Xuan

Huili Li

Ju Jiao

Hongwu Zhang

Romain Gautier

Jing Wang
title: Chemical Transformation of Lead Halide Perovskite into Insoluble, Less Cytotoxic, and Brightly Luminescent CsPbBr3/CsPb2Br5 Composite Nanocrystals for Cell Imaging.
venue: ACS applied materials interfaces
year: 2019

abstract: Abstract Solution processed all inorganic trihalide perovskite nanocrystals are potential materials for the fabrication of future generation optoelectronic devices. However, the surface of the perovskite nanocrystals should be encapsulated to prevent degradation. Because of their stability under ambient conditions, nanocomposites of perovskite nanocrystals have been intensively researched for display applications. Perovskite nanocrystals dispersion or growth in a polymer matrix imparts structural stability and influences the optical properties, preventing effects such as halide migration. Developing flexible, high performance lighting devices through perovskite nanocomposites will need to be evaluated on the compatibility of nanocrystals within the polymer matrix. Research in this area has escalated, but specific attention is required to address the practical challenges. This chapter discusses the current developments in the field of preparation and processing of nanocomposites of pure inorganic perovskite nanocrystals. Organic ligands, fabrication methods, encapsulating compounds, solvents, and other deposition procedures affecting the performance and stability of nanocomposites are discussed.
author_names: Ananthakumar Soosaimanickam

Pedro J rodriguez-Canto

Juan P Martinez-Pastor

Rafael Abargues
title: Preparation and processing of nanocomposites of all inorganic lead halide perovskite nanocrystals
year: 2021

abstract: Thermally activated delayed fluorescence (TADF) is generally observed in solid state organic molecules or metal organic complexes. However, TADF in all inorganic colloidal nanocrystals (NCs) is rare. Herein, we report the first colloidal synthesis of an air stable all inorganic lead free Cs 2 ZrCl 6 perovskite NCs. The Cs 2 ZrCl 6 NCs exhibit long lived triplet excited state (138.2 ms) featuring highly efficient photoluminescence (PL) quantum efficiency (QY= 60.37% due to TADF. The emission color can be easily tuned from blue to green by synthesizing the mixed halide Cs 2 ZrBr x Cl 6 x (0<=x<=1.5) NCs. Both femtosecond transient absorption and temperature dependent PL measurements are performed to clarify the emission mechanism. In addition, Bi 3+ ions are successfully doped into Cs 2 ZrCl 6 NCs, which further extends the PL properties. This work not only develops a new lead free perovskite Cs 2 ZrCl 6 NCs for potential optoelectronic applications, but also offers unique strategies for developing new inorganic phosphors.
author_names: Siping Liu

Bin Yang

Junsheng Chen

Daoyuan Zheng

Qingkun Kong

Weiqiao Deng

Keli Han
title: Efficient Thermally Activated Delayed Fluorescence from All Inorganic Cesium Zirconium Halide Perovskite Nanocrystals.
venue: Angewandte Chemie
year: 2020

abstract: Recently, all inorganic cesium lead halide (CsPbX3, X Cl, Br, and I) nanocrystals (NCs) have drawn wide attention because of their excellent optoelectronic properties and potential applications. However, one of the most significant challenges of such NCs is their low stability against protonic solvents. In this work, we demonstrate that by incorporating a highly branched capping ligand, trioctylphosphine oxide (TOPO) into the traditional oleic acid/oleylamine system, monodisperse CsPbX3 NCs with excellent optoelectronic properties can be achieved at elevated temperatures (up to 260 degC) The size of such NCs can be varied in a relatively wide range. The capping of TOPO on NCs has been verified through Fourier transform infrared spectroscopy measurement. More importantly, the presence of TOPO can dramatically improve the stability of CsPbX3 NCs against ethanol treatment. After ethanol treatment for 100 min, the emission intensity of the TOPO capped sample dropped only 5% whereas that of non TOPO capped NCs dropped up to 86% This work may shed some light on the preparation and application of CsPbX3 NCs with higher stability.
author_names: Linzhong Wu

Qixuan Zhong

Di Yang

Min Chen

Huicheng Hu

Qi Pan

Haiyu Liu

Muhan Cao

Yong Xu

Baoquan Sun

Qiao Zhang
title: Improving the Stability and Size Tunability of Cesium Lead Halide Perovskite Nanocrystals Using Trioctylphosphine Oxide as the Capping Ligand.
venue: Langmuir the ACS journal of surfaces and colloids
year: 2017

abstract: Lead based perovskite nanocrystals (NCs) have outstanding optical properties and cheap synthesis conferring them a tremendous potential in the field of optoelectronic devices. However, two critical problems are still unresolved and hindering their commercial applications: one is the fact of being lead based and the other is the poor stability. Lead free all inorganic perovskite Cs3 Bi2 X9 (X=Cl, Br, I) NCs are synthesized with emission wavelength ranging from 400 to 560 nm synthesized by a facile room temperature reaction. The ligand free Cs3 Bi2 Br9 NCs exhibit blue emission with photoluminescence quantum efficiency (PLQE) about 0.2 The PLQE can be increased to 4.5 when extra surfactant (oleic acid) is added during the synthesis processes. This improvement stems from passivation of the fast trapping process (2 20 ps) Notably, the trap states can also be passivated under humid conditions, and the NCs exhibited high stability towards air exposure exceeding 30 days.
author_names: Bin Yang

Junsheng Chen

Feng Hong

Xin Mao

Kaibo Zheng

Songqiu Yang

Yajuan Li

Tonu Pullerits

Weiqiao Deng

Keli Han
title: Lead Free, Air Stable All Inorganic Cesium Bismuth Halide Perovskite Nanocrystals.
venue: Angewandte Chemie
year: 2017

abstract: Lead halide perovskite materials are thriving in optoelectronic applications due to their excellent properties, while their instability due to the fact that they are easily hydrolyzed is still a bottleneck for their potential application. In this work, water resistant, monodispersed and stably luminescent cesium lead bromine perovskite nanocrystals coated with CsPb2Br5 were obtained using a modified non stoichiometric solution phase method. CsPb2Br5 2D layers were coated on the surface of CsPbBr3 nanocrystals and formed a core shell like structure in the synthetic processes. The stability of the luminescence of the CsPbBr3 nanocrystals in water and ethanol atmosphere was greatly enhanced by the photoluminescence inactive CsPb2Br5 coating with a wide bandgap. The water stable enhanced nanocrystals are suitable for long term stable optoelectronic applications in the atmosphere.
author_names: Bo Qiao

Pengjie Song

Jingyue Cao

Suling Zhao

Zhaohui Shen

Zhiqin Liang

Zheng Xu

Dan-dan Song

Xurong Xu
title: Water resistant, monodispersed and stably luminescent CsPbBr3/CsPb2Br5 core shell like structure lead halide perovskite nanocrystals.
venue: Nanotechnology
year: 2017

abstract: Lead based perovskite nanocrystals (NCs) have demonstrated outstanding optical properties and cheap synthesis methods conferring them a tremendous potential in the field of optoelectronic devices. However,two critical problems are still unresolved and hindering their commercial applications: one is the fact of being lead based and the other is the poor stability. Here, we report alead free all inorganic perovskite Cs3Bi2X9(X= Cl, Br, I)NCswith emission wavelength ranging from 400 to 560 nm synthesized by a facile room temperature reaction. The ligand free Cs3Bi2Br9NCs exhibits blue emission with photoluminescence quantum efficiency (PLQE) about 0.2% The PLQE can be increased to 5 when extra surfactant (oleic acid) is added during the synthesis processes.We determine that this improvement stems from passivationoffast trapping process (2~20 ps) Notably the trap states can also be passivated in humid condition and the NCs exhibited high stabilitytowards air exposure exceeding 30 days.
author_names: Ke-Li Han

Bin Yang

Junsheng Chen

Feng Hong

Xin Mao

Kaibo Zheng

Songqiu Yang

Yajuan Li

Tonu Pullerits

Wei-Qiao Deng
title: Lead Free, All Inorganic Cesium Bismuth Halide Perovskite Nanocrystals with Long Term Stability
year: 2017