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Harnessing Hot Phonon Bottleneck in Metal Halide Perovskite Nanocrystals via Interfacial Electron-Phonon Coupling.
Nano Letters ( IF 9.6 ) Pub Date : 2020-05-18 , DOI: 10.1021/acs.nanolett.0c01452
Zhonghui Nie 1 , Xuanzhao Gao 2 , Yinjuan Ren 3 , Siyang Xia 1 , Yuhan Wang 4 , Yongliang Shi 2 , Jin Zhao 2 , Yue Wang 1
Affiliation  

Slow hot carrier (HC) cooling resulting from hot phonon bottleneck has been widely demonstrated in metal halide perovskites. Although manipulating HC kinetics in these materials is of both fundamental and technological importance, this task remains a daunting challenge. Here, via interfacial engineering, i.e., epitaxial growth of Cs4PbBr6 on CsPbBr3 nanocrystals (NCs), we have revealed an obvious shortening of HC cooling times, evidenced by transient absorption and ultrafast PL spectra. Collaborated with the longitudinal optical (LO) phonon model, theoretical calculations verify the breaking of the hot phonon bottleneck in CsPbBr3@Cs4PbBr6 and identify the interfacial electron-LO phonon coupling as the leading mechanism for the observed large tuning of HC cooling times. Especially, the participation of LO phonons from Cs4PbBr6 enables the efficient Klemens channel for hot phonon decay. Our findings establish an effective method to tailor HC dynamics in perovskite NCs, which could be conducive to improving the performance of optoelectronic applications.

中文翻译:

通过界面电子-声子耦合来控制金属卤化物钙钛矿纳米晶体中的热声子瓶颈。

在金属卤化物钙钛矿中已广泛证明了由热声子瓶颈引起的慢速热载体(HC)冷却。尽管在这些材料中控制HC动力学具有根本和技术重要性,但这项任务仍然是艰巨的挑战。在这里,通过界面工程,即CsPbBr 3纳米晶体(NCs)上Cs 4 PbBr 6的外延生长,我们发现了HC冷却时间明显​​缩短,这由瞬态吸收和超快PL光谱证明。理论计算与纵向光学(LO)声子模型协作,验证了CsPbBr 3 @Cs 4 PbBr 6中热声子瓶颈的打破并确定界面电子-LO声子耦合是观察到的大的HC冷却时间调谐的主要机制。特别是,来自Cs 4 PbBr 6的LO声子的参与为热声子衰变提供了有效的Klemens通道。我们的发现建立了一种有效的方法,可以调整钙钛矿型NC中的HC动力学,这可能有助于改善光电应用的性能。
更新日期:2020-05-18
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