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

Abstract

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 fullspectra 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 redemitting counterparts. Herein, we obtained core−shell structured cubic CsPbBr 3 @amorphous CsPbBr x (A-CsPbBr x ) 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 CsPbBr 3 QDs and CsPbBr x Cl 3−x QDs. Furthermore, a blue-emitting QDsassisted LED with bright pure blue emission was prepared and illustrated the core−shell QDs' promising prospect in optoelectrical application.

Surface Trap States Passivation for High‐Performance Inorganic Perovskite Solar Cells

“…Some additives have been exploited to stabilize the α‐CsPbI 3 by reducing grain size with enlarging the surface energy, such as HI, ethylenediamine (EDA) cation, sulfobetaine zwitterions, and polymer poly‐vinylpyrrolidone (PVP) . The same principle, synthesizing CsPbI 3 quantum dots (QDs) is another promising method to stabilize cubic phase at room temperature . Nevertheless, the superabundant grain boundaries and long‐chain surfactants would suppress carriers transport.…”

Light Generation in Lead Halide Perovskite Nanocrystals: LEDs, Color Converters, Lasers, and Other Applications

“…In practice, the defects of vacancies or surface dangling bonds and grain boundaries make it difficult to represent LHP‐NCs by a stoichiometric formula. When grain boundaries are neglected, under ideal conditions, LHP‐NCs can be expressed by the chemical formula ( R ) 2 (A) n −1 B n X 3 n +1 , where site‐A is an amine cation, e.g., formamidinium (FA) or methylammonium (MA) or Cs + ; site‐B is Pb 2+ ; and site‐X is Cl − , Br − , or I − . For n = 1, the abovementioned formula can be predigested into a monolayer of 2D R 2 BX 4 , where R is a molecular ligand sandwiching a corner‐sharing [PbX 6 ] 4− octahedral perovskite sheet ( Figure a) .…”

Pure Bromide‐Based Perovskite Nanoplatelets for Blue Light‐Emitting Diodes

“…Wang et al increased the size of pure bromide perovskites (CsPbBr 3 @amorphous–CsPbBr x nanospheres) to 6 nm while maintaining blue emission. They showed a PLQY over 80% but the FWHM was still larger than 32 nm …”

“…Another all‐perovskite core–shell structure of cubic CsPbBr 3 @amorphous CsPbBr x nanocrystals was gained through a facile hot injection method . The 2 nm sized cubic phase of CsPbBr 3 was surrounded by a layer of amorphous CsPbBr x , which acted as a protective shell.…”