| 研究実績の概要 |
The purpose of the project is to study the basic photophysical properties of single halide perovskite nanocrystals by photoluminescence (PL) and electroluminescence (EL) single-particle spectroscopy. In the past year, the research continued on the mechanism and methods of suppression of PL blinking by ligand engineering of the CsPbBr3 nanocrystals. Replacement of the oleyl amine and oleyl acid ligands with shorter and more strongly bound DDAB ligands lead to significant suppression of blinking due to passivation of surface traps. The passivated nanocrystals were further used in a single-particle EL device. The ligand exchange lead to the successful observation of EL and confirmation of perovskite EL spectra. Concentration adjustment and the measurement of photon antibunching will be further necessary to confirm single photon EL emission from individual nanocrystals.
Research continued also on a series of mixed cation (MA/FA) hybrid organo-metallic halide perovskite films and their nanoscale properties by PL microspectroscopy. It was found that films with 50% and 30% content of the FA cation prepared in air using ethyl acetate as an antisolvent are compositionally stable in ambient air for more than a year, in contrast to films prepared using a chlorobenzene antisolvent. The onset of degradation of the films near the film edges was monitored using in situ PL spectroscopy.
The PL spectra of the degradation products are consistent with the PL spectra of 2D perovskite sheets of varying thicknesses.
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