Single-particle electroluminescence of CsPbBr3 perovskite nanocrystals reveals particle-selective recombination and blinking as key efficiency factors
Single-particle electroluminescence of CsPbBr3 perovskite nanocrystals reveals particle-selective recombination and blinking as key efficiency factors
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DOI：
10.1038/s41467-019-12512-y
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发表时间：
2019-10-03
影响因子：
16.6
通讯作者：
Vacha, Martin
中科院分区：
文献类型：
--
作者：
Sharma, Dharmendar Kumar;Hirata, Shuzo;Vacha, Martin
卤化物钙钛矿纳米晶体（NC）正在被探索作为光电应用的有前途的材料，如发光器件或激光器。然而，从这样的纳米碳制备的电致发光器件长期以来一直遭受低效率，并没有系统的研究，在纳米级的低效率的起源。在这里，我们使用单粒子光谱来比较钙钛矿CsPbBr3的单个NC水平上的电致发光和光致发光。NC在用作电致发光器件中的发射层的导电基质中形成聚集体。在电致发光中，聚集体中只有一小部分的NC由于较大NC上的有效电荷迁移、积累和选择性复合而发光，导致明显的闪烁和效率降低。在光致发光和电致发光激发速率相当的条件下，电致发光的本征量子产额平均为光致发光的0.36。
Halide perovskites nanocrystals (NCs) are being explored as promising materials for optoelectronic applications, such as light-emitting devices or lasers. However, electroluminescence devices prepared from such NCs have long suffered from low efficiency and there has been no systematic study on the nanoscale origin of the poor efficiencies. Here, we use single-particle spectroscopy to compare electroluminescence and photoluminescence on the level of individual NCs of the perovskite CsPbBr3. The NCs form aggregates in a conducting matrix used as an emission layer in an electroluminescence device. In electroluminescence, only a small fraction of the NCs within the aggregate is emitting as a result of efficient charge migration, accumulation and selective recombination on larger NCs, leading to pronounced blinking and decreased efficiency. Under the condition of comparable excitation rates in both electroluminescence and photoluminescence, the intrinsic quantum yield in electroluminescence is on average 0.36 of that in photoluminescence.