铯-铅-卤化物钙钛矿量子点中单激子，双激子和三子的光谱和动力学性质,Nano Letters

当前位置： X-MOL 学术 › Nano 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.)

铯-铅-卤化物钙钛矿量子点中单激子，双激子和三子的光谱和动力学性质
Nano Letters ( IF 9.6 ) Pub Date : 2016-03-01 00:00:00 , DOI: 10.1021/acs.nanolett.5b05077
Nikolay S. Makarov ₁ , Shaojun Guo ₁ , Oleksandr Isaienko ₁ , Wenyong Liu ₁ , István Robel ₁ , Victor I. Klimov ₁

Affiliation

由于其非凡的光伏性能，有机-无机卤化铅钙钛矿已成为近期引起人们极大关注的主题。钙钛矿家族的一个新成员是通过中温胶体合成制备的全无机Cs-Pb-卤化物钙钛矿纳米晶体或量子点。这些纳米材料虽然只是在最近才被引入研究领域，但它们已经显示出了从彩色转换磷光体和发光二极管到激光器甚至室温单光子源的一系列应用前景。关于钙钛矿量子点的光学性质的知识仍然非常不完整。在这里，我们应用各种时间分辨光谱技术对CsPbX中单激子态和多激子态的光谱和动力学特性进行了全面的研究。₃X是Br，I或它们的混合物的纳米晶体。具体来说，我们测量激子的辐射寿命，吸收截面，并得出带边缘电子和空穴态的简并性。我们还表征了带内冷却和非辐射俄歇复合的速率，并评估了激子-激子耦合的强度。这项工作的总体结论是，Cs–Pb-卤化物量子点的光谱性质与CdSe和PbSe等更传统的半导体的量子点的光谱性质非常相似。同时，我们观察到了一些区别，例如，卤化物的身份对辐射寿命有明显影响，双激子俄歇寿命大大缩短，并且其大小依赖性的明显偏差与先前在许多传统纳米晶体系统中观察到的“通用体积缩放”有关。钙钛矿量子点中俄歇衰变的高效率不利于它们在发光设备和激光器中的预期应用。这表明有必要开发一些方法来有效地抑制这些纳米材料中的俄歇复合现象，这可能要使用从先前对II–VI纳米晶体的研究中获得的见识。

"点击查看英文标题和摘要"

Spectral and Dynamical Properties of Single Excitons, Biexcitons, and Trions in Cesium–Lead-Halide Perovskite Quantum Dots

Organic–inorganic lead-halide perovskites have been the subject of recent intense interest due to their unusually strong photovoltaic performance. A new addition to the perovskite family is all-inorganic Cs–Pb-halide perovskite nanocrystals, or quantum dots, fabricated via a moderate-temperature colloidal synthesis. While being only recently introduced to the research community, these nanomaterials have already shown promise for a range of applications from color-converting phosphors and light-emitting diodes to lasers, and even room-temperature single-photon sources. Knowledge of the optical properties of perovskite quantum dots still remains vastly incomplete. Here we apply various time-resolved spectroscopic techniques to conduct a comprehensive study of spectral and dynamical characteristics of single- and multiexciton states in CsPbX₃ nanocrystals with X being either Br, I, or their mixture. Specifically, we measure exciton radiative lifetimes, absorption cross-sections, and derive the degeneracies of the band-edge electron and hole states. We also characterize the rates of intraband cooling and nonradiative Auger recombination and evaluate the strength of exciton–exciton coupling. The overall conclusion of this work is that spectroscopic properties of Cs–Pb-halide quantum dots are largely similar to those of quantum dots of more traditional semiconductors such as CdSe and PbSe. At the same time, we observe some distinctions including, for example, an appreciable effect of the halide identity on radiative lifetimes, considerably shorter biexciton Auger lifetimes, and apparent deviation of their size dependence from the “universal volume scaling” previously observed for many traditional nanocrystal systems. The high efficiency of Auger decay in perovskite quantum dots is detrimental to their prospective applications in light-emitting devices and lasers. This points toward the need for the development of approaches for effective suppression of Auger recombination in these nanomaterials, using perhaps insights gained from previous studies of II–VI nanocrystals.

更新日期：2016-03-01

点击分享查看原文

点击收藏

公开下载

阅读更多本刊最新论文本刊介绍/投稿指南

全部期刊列表>>