| 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 and electroluminescence single-particle spectroscopy, with the perspective of development towards nanoscale light-emitting optoelectronic devices. The methodology is based on measurement and analysis of emission intensity time traces, spectra and excited state lifetimes. The key questions include origin and methods of suppression of blinking in both EL and PL, origin of spectral diffusion in relationship with structural/compositional stability, and effect of surface functionalization and nanocrystal orientation on the effectivity of charge transport and charge recombination.
In the past year, research began on elucidation of the blinking mechanism in single nanocrystals of CsPbBr3 in both photo- and electroluminescence. The strategy for the study of the origin of blinking in photoluminescence included the use of different environment represented by matrices of varying energy levels, dielectric function and conductivity. Initial results confirmed that the environment plays a determining role in the nanocrystal blinking. In electroluminescence, the aim was to construct devices which would involve an emitting layer composed of single nanocrystals dispersed in an insulating matrix, sandwiched between two electrodes.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
The study of the origin of photoluminescence blinking in single perovskite nanocrystals proceeded mainly according to the original plan. Use of different matrices lead to qualitatively different blinking patterns which reflect different blinking mechanisms.
The study of the blinking phenomenon in electroluminescence, on the other hand, was delayed due to the breakdown of the film evaporation setup and the necessary repair. After the repair, initial experiments confirmed successful observation of electroluminescence from perovskite nanocrystals dispersed in films of PMMA.
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| 今後の研究の推進方策 |
This year, the work on elucidating the mechanism of blinking in photoluminescence and electroluminescence will continue. Specifically, the single nanocrystals of CsPbBr3 will be dispersed in different polymer matrices such as inert PMMA or PS, and conductive PVK. Further, small-molecule conductive films such as PBD will be explored. In addition to recording of intensity time traces, the analysis will involve probability distribution functions, and experiments will be extended to measurements of excitation intensity dependence or to correlations between blinking intensity and photoluminescence lifetimes.
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