Energy localization vs. charge funneling in aggregates of CsPbBr3 perovskite nanocrystals
Energy localization vs. charge funneling in aggregates of CsPbBr3 perovskite nanocrystals
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DOI：
10.1016/j.jlumin.2020.117119
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发表时间：
2020-06
影响因子：
3.6
通讯作者：
D. Sharma;S. Hirata;M. Vacha
中科院分区：
文献类型：
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作者：
D. Sharma;S. Hirata;M. Vacha
我们研究了卤化物钙钛矿CsPbBr3由数十到数百个纳米晶组成的单一聚集体的光致发光和电致发光。由NCS的尺寸分布引起的聚集体的能量格局导致电荷从最大的NC流向和从最大的NC漏斗。这种现象导致聚集EL的明显闪烁。另一方面，在光致发光中，吸收的光能被局域化并重新发射到单个NCS上，而不是通过能量/激子转移进行显著的重新分配。因此，单个聚集体的PL不会显示任何闪烁。我们进一步研究了外加直流电压对类电容器件中聚集体发光的影响，观察到了一个有趣的现象，即发光强度以秒为周期出现，并且不同聚集体之间的发光强度在微米距离上是相互关联的。
We studied photoluminescence (PL) and electroluminescence (EL) on single aggregates composed of tens to hundreds of nanocrystals (NCs) of the halide perovskite CsPbBr3. Energy landscape of the aggregate caused by size distribution of the NCs leads to funneling of charges towards and EL from the largest NC. This phenomenon results in pronounced blinking of the aggregate EL. In PL, on the other hand, the absorbed light energy is localized and reemitted on individual NCs, without significant redistribution by energy/exciton transfer. As a result the PL of individual aggregates does not show any blinking. We further investigated the effect of externally applied dc voltage on PL of the aggregates in a capacitance-like device and observed an intriguing phenomenon of large oscillations of PL intensity that occur with a period of seconds and are correlated between different aggregates across micrometer distances.