The colloidal semiconductor nanoplatelet (NPL) with broad ligand-semiconductor interface is an ideal system for surface science investigation, but the study regarding depletion effects in NPLs remains lacking. Herein we explore such effects in colloidal CdSe NPLs through Br ligation. Apart from improved brightness and red-shifted optical features, we also experimentally observed abnormal negative thermal quenching phenomena in bromide-ligated CdSe NPLs over 200 K under a cryogenic environment and up to 383 K under an ambient environment, which was absent in pristine NPLs. We speculate that the surface depletion effect shall account for these anomalous phenomena due to the susceptibility of the surface depletion region on photoexcited carrier concentration and surface condition. The existence of the depletion layer in NPLs is also validated quantitatively with k·p simulation. Besides offering an alternative explanation on the red-shifted optical properties of CdSe NPLs by Br-ligation, our findings pave the new route toward solution-processed NPLs-based optoelectronics with boosted thermal resistance.

中文翻译：

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溴化物连接胶体硒化镉纳米血小板的表面消耗效应：在高温下实现高效发射

具有宽配体-半导体界面的胶体半导体纳米血小板 (NPL) 是表面科学研究的理想系统，但关于 NPL 耗尽效应的研究仍然缺乏。在此，我们通过 Br 连接探索胶体 CdSe NPL 中的这种影响。除了提高亮度和红移光学特征外，我们还通过实验观察到溴化物连接的 CdSe NPL 在低温环境下超过 200 K 和在环境环境下高达 383 K 的异常负热猝灭现象，这在原始 NPL 中是不存在的。我们推测，由于表面耗尽区对光激发载流子浓度和表面条件的敏感性，表面耗尽效应应解释这些异常现象。k·p模拟。除了通过 Br 连接对 CdSe NPL 的红移光学性质提供另一种解释外，我们的研究结果还为解决方案处理的 NPL 基光电子学提供了新的途径，并提高了热阻。