权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Study of electroluminescence and photophysical properties of single halide perovskite nanocrystals

单卤化物钙钛矿纳米晶的电致发光和光物理性质研究

基本信息

批准号：
19H02684
负责人：
VACHA Martin
金额：
$ 11.48万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2019
资助国家：
日本
起止时间：
2019-04-01 至 2024-03-31
项目状态：
已结题

项目摘要

In the past year, the research on the mechanism and methods of suppression of PL blinking included ligand engineering of the CsPbBr3 nanocrystals. Focus was placed on reproducibility of the nanocrystal synthesis and ligand exchange, as well as on the effect of the ligands on the nanocrystal aging. Further, a series of mixed cation (MA/FA) hybrid organo-metallic halide perovskite films were fabricated and their nanoscale properties were studied using PL microspectroscopy. PL spectra measured on sub-micrometer revealed large compositional heterogeneity of the films. The heterogeneity was largest for the FA 50% fraction films which contain purely MA domains, purely FA domains, as well as domains composed of mixed MA/FA cations of varying ratios. The films also showed PL blinking which reflects dynamic non-radiative quenching. The quenching was most suppressed for the FA 50% films which indicates that the truly mixed MA/FA domains are least affected by the non-radiative losses. Further, the PL blinking was correlated between locations that are several micrometers apart, indicating that the grain boundaries do not represent barriers for charge transport and do not work as charge traps, enabling efficient charge migration over micrometer distances. The blinking behavior was also affected by externally applied electric field, which additionally causes large fluctuations of PL spectra that are explained by field-induced I- ion migration.

在过去的一年里，抑制PL闪烁的机理和方法的研究包括CsPbBr3纳米晶的配体工程。重点研究了纳米晶合成和配体交换的重现性，以及配体对纳米晶老化的影响。在此基础上，制备了一系列混合阳离子(MA/FA)杂化有机金属卤化物钙钛矿薄膜，并用荧光显微光谱研究了它们的纳米尺度性质。亚微米光致发光光谱表明，薄膜的成分具有很大的不均一性。对于含有纯MA结构域、纯FA结构域以及由不同比例的MA/FA混合阳离子组成的结构域的FA含量为50%的薄膜，其不均匀程度最大。薄膜还显示了发光闪烁，这反映了动态的非辐射猝灭。对于FA为50%的薄膜，猝灭的抑制程度最大，这表明真正混合的MA/FA结构域受非辐射损失的影响最小。此外，发光闪烁在相隔几微米的位置之间相互关联，表明晶界并不代表电荷传输的障碍，也不起电荷陷阱的作用，从而实现了电荷在微米距离上的有效迁移。闪烁行为还受到外加电场的影响，外加电场还会导致发光光谱的大幅波动，这可以用场诱导的I-离子迁移来解释。