Metal halide perovskites represent a flourishing area of research, driven by both their potential application in photo-voltaics and optoelectronics, and for the fundamental science underpinning their unique optoelectronic properties. The advent of colloidal methods for the synthesis of halide perovskite nanocrystals has brought to the attention inter-esting aspects of this new type of materials, above all their defect-tolerance. This review aims to provide an updated survey of this fast-moving field, with a main focus on their colloidal synthesis. We examine the chemistry and the ca-pability of different colloidal synthetic routes to control the shape, size and optical properties of the resulting nano-crystals. We also provide an up to date overview of their post-synthesis transformations, and summarize the various so-lution processes aimed at fabricating halide perovskite-based nanocomposites. We then review the fundamental optical properties of halide perovskite nanocrystals, by focusing on their linear optical properties, on the effects of quantum confinement and, then, on the current knowledge of their exciton binding energies. We also discuss the emergence of non-linear phenomena such as multiphoton absorption, biexcitons and carrier multiplication. At last, we provide an outlook in the field, with the most cogent open questions and possible future directions.

Metal Halide Perovskite Nanocrystals: Synthesis, Post-Synthesis Modifications and Their Optical Properties

Metal halide perovskites represent a flourishing area of research, which is driven by both their potential application in photovoltaics and optoelectronics and by the fundamental science behind their unique optoelectronic properties. The emergence of new colloidal methods for the synthesis of halide perovskite nanocrystals, as well as the interesting characteristics of this new type of material, has attracted the attention of many researchers. This review aims to provide an up-to-date survey of this fast-moving field and will mainly focus on the different colloidal synthesis approaches that have been developed. We will examine the chemistry and the capability of different colloidal synthetic routes with regard to controlling the shape, size, and optical properties of the resulting nanocrystals. We will also provide an up-to-date overview of their postsynthesis transformations, and summarize the various solution processes that are aimed at fabricating halide perovskite-based nanocomposites. Furthermore, we...

Metal Halide Perovskite Nanocrystals: Synthesis, Post-Synthesis Modifications, and Their Optical Properties.

Beyond the unprecedented success achieved in photovoltaics (PVs), lead halide perovskites (LHPs) have shown great potential in other optoelectronic devices. Among them, nanometer-scale perovskite quantum dots (PQDs) with fascinating optical properties including high brightness, tunable emission wavelength, high color purity, and high defect tolerance have been regarded as promising alternative down-conversion materials in phosphor-converted light-emitting diodes (pc-LEDs) for lighting and next-generation of display technology. Despite the promising applications of perovskite materials in various fields, they have received strong criticism for the lack of stability. The poor stability has also attracted much attention. Within a few years, numerous strategies towards enhancing the stability have been developed. This review summarizes the mechanisms of intrinsic- and extrinsic-environment-induced decomposition of PQDs. Simultaneously, the strategies for improving the stability of PQDs are reviewed in detail, which can be classified into four types: (1) compositional engineering; (2) surface engineering; (3) matrix encapsulation; (4) device encapsulation. Finally, the challenges for applying PQDs in pc-LEDs are highlighted, and some possible solutions to improve the stability of PQDs together with suggestions for further improving the performance of pc-LEDs as well as the device lifetime are provided.

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An overview on enhancing the stability of lead halide perovskite quantum dots and their applications in phosphor-converted LEDs

This review captures the synthesis, assembly, properties, and applications of copper chalcogenide NCs, which have achieved significant research interest in the last decade due to their compositional and structural versatility. The outstanding functional properties of these materials stems from the relationship between their band structure and defect concentration, including charge carrier concentration and electronic conductivity character, which consequently affects their optoelectronic, optical, and plasmonic properties. This, combined with several metastable crystal phases and stoichiometries and the low energy of formation of defects, makes the reproducible synthesis of these materials, with tunable parameters, remarkable. Further to this, the review captures the progress of the hierarchical assembly of these NCs, which bridges the link between their discrete and collective properties. Their ubiquitous application set has cross-cut energy conversion (photovoltaics, photocatalysis, thermoelectrics), en...

Compound Copper Chalcogenide Nanocrystals

Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of perovskite nanocrystals and understanding of their properties and applications. In this comprehensive review, researchers having expertise in different fields (chemistry, physics, and device engineering) of metal-halide perovskite nanocrystals have joined together to provide a state of the art overview and future prospects of metal-halide perovskite nanocrystal research.

State of the Art and Prospects for Halide Perovskite Nanocrystals.

All-inorganic perovskite quantum dots (QDs) have emerged as potentially promising materials for lighting and displays, but their poor thermal stability restricts their practical application. In addition, optical characteristics of the blue-emitting CsPbX3 QDs lag behind their red- and green-emitting counterparts. Herein, we addressed these two issues by doping divalent Cu2+ ions into the perovskite lattice to form CsPb1–xCuxX3 QDs. Extended X-ray absorption fine structure (EXAFS) measurements reveal that doping smaller Cu2+ guest ions induces a lattice contraction and eliminates halide vacancies, which leads to an increased lattice formation energy and improved short-range order of the doped perovskite QDs. This results in the improvement of both the thermal stability and the optical performance of CsPb1–xCux(Br/Cl)3 QDs, which exhibit bright blue photoluminescence at 450–460 nm, with a high quantum yield of over 80%. The CsPb1–xCuxX3 QD films maintain stable luminescence performance even when annealed at...

Thermally Stable Copper(II)-Doped Cesium Lead Halide Perovskite Quantum Dots with Strong Blue Emission

All-inorganic perovskite cesium lead halide quantum dots (QDs) have been widely investigated as promising materials for optoelectronic application because of their outstanding photoluminescence (PL) properties and benefits from quantum effects. Although QDs with full-spectra visible emission have been synthesized for years, the PL quantum yield (PLQY) of pure blue-emitting QDs still stays at a low level, in contrast to their green- or red-emitting counterparts. Herein, we obtained core–shell structured cubic CsPbBr3@amorphous CsPbBrx (A-CsPbBrx) perovskite QDs via a facile hot injection method and centrifugation process. The core–shell structure QDs showed a record blue emission PLQY of 84%, which is much higher than that of blue-emitting cubic CsPbBr3 QDs and CsPbBrxCl3–x QDs. Furthermore, a blue-emitting QDs-assisted LED with bright pure blue emission was prepared and illustrated the core–shell QDs’ promising prospect in optoelectrical application.

Original Core–Shell Structure of Cubic CsPbBr3@Amorphous CsPbBrx Perovskite Quantum Dots with a High Blue Photoluminescence Quantum Yield of over 80%

Spray-Coated Colloidal Perovskite Quantum Dot Films for Highly Efficient Solar Cells

All inorganic halide perovskites in the form of colloidal quantum dots (QDs) have come into people’s view as one of potential materials for the high-efficiency solar cells, nevertheless, the high s

Stable CsPb1–xZnxI3 Colloidal Quantum Dots with Ultralow Density of Trap States for High-Performance Solar Cells

All-inorganic cesium lead halide perovskite quantum dots (QDs) are attractive potential materials for high-performance optoelectronics because of their high photoluminescence quantum yield (PLQY), ...

Shixun Wang

Papers

Thermally Stable Copper(II)-Doped Cesium Lead Halide Perovskite Quantum Dots with Strong Blue Emission

Original Core–Shell Structure of Cubic CsPbBr3@Amorphous CsPbBrx Perovskite Quantum Dots with a High Blue Photoluminescence Quantum Yield of over 80%

Spray-Coated Colloidal Perovskite Quantum Dot Films for Highly Efficient Solar Cells

Stable CsPb1–xZnxI3 Colloidal Quantum Dots with Ultralow Density of Trap States for High-Performance Solar Cells

Room-Temperature Construction of Mixed-Halide Perovskite Quantum Dots with High Photoluminescence Quantum Yield