Carrier Multiplication and Hot-Carrier Cooling Dynamics in Quantum-Confined CsPbI3 Perovskite Nanocrystals,The Journal of Physical Chemistry Letters

当前位置： X-MOL 学术 › J. Phys. Chem. Lett. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Carrier Multiplication and Hot-Carrier Cooling Dynamics in Quantum-Confined CsPbI3 Perovskite Nanocrystals
The Journal of Physical Chemistry Letters ( IF 4.8 ) Pub Date : 2020-02-24 , DOI: 10.1021/acs.jpclett.0c00188
Muyu Cong _{1,

2} , Bin Yang ₁ , Junsheng Chen ₁ , Feng Hong _{1,

2} , Songqiu Yang ₁ , Weiqiao Deng _{1,

3} , Keli Han _{1,

3}

Affiliation

Carrier multiplication (CM) is an effective mechanism that makes it possible to use hot carriers (HCs) to bypass the Shockley–Queisser limit for solar-cell efficiency. In this paper, we present a detailed study of both CM and HC cooling dynamics in quantum-confined CsPbI₃ perovskite nanocrystals (NCs), using femtosecond transient absorption spectroscopy. Our results show that barrierless CM, with an efficiency exceeding 90%, can be achieved in strongly confined NCs on a time scale of ≪200 fs. A low CM efficiency (∼40%), however, is observed in weakly confined NCs. HC cooling dynamics suggests the absence of an intrinsic phonon bottleneck in strongly confined NCs. Furthermore, the biexciton Auger rate increased 4-fold in strongly confined NCs compared to that in weakly confined NCs. These results suggest that the enhanced CM in strongly confined NCs likely originates from enhanced Coulomb coupling and relaxed momentum conservation.

中文翻译：

量子限制的CsPbI ₃钙钛矿纳米晶体中的载流子增殖和热载流子冷却动力学。

载流子倍增（CM）是一种有效的机制，可以使热载流子（HC）绕过Shockley-Queisser限制，以提高太阳能电池的效率。在本文中，我们对量子受限的CsPbI _3中的CM和HC冷却动力学进行了详细研究。钙钛矿纳米晶体（NCs），使用飞秒瞬态吸收光谱法。我们的结果表明，在高度受限的NC中，可以在f200 fs的时间范围内实现效率超过90％的无障碍CM。然而，在弱约束的NC中观察到较低的CM效率（约40％）。HC冷却动力学表明，在高度受限的NC中不存在固有的声子瓶颈。此外，与弱约束NCs相比，双约束俄歇率在强约束NCs中增加了4倍。这些结果表明，强约束NC中增强的CM可能源自增强的库仑耦合和松弛的动量守恒。

更新日期：2020-02-25

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11