Wang Hua, Zhang Xiangtong, Sui Ning, Hu Yue, Colvin Vicki L, Yu William W, Zhang Yu
State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China.
College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
ACS Appl Mater Interfaces. 2020 Mar 11;12(10):11769-11777. doi: 10.1021/acsami.9b23556. Epub 2020 Feb 27.
α-CsPbI perovskite quantum dots (PQDs) have great potentials in red-emitting LED and solar cell applications. However, their instability with quick photoluminescence loss with time greatly limits their development. In this study, we found that the nonluminous aged α-CsPbI PQDs instantly regained fluorescence emission after a surface treatment with trioctylphosphine. Meanwhile, this surface treatment also worked on fresh α-CsPbI PQDs to enhance photoluminescence emission. The structures and compositions of fresh and aged PQDs before and after surface treatment were analyzed in detail. We demonstrated that a surface chemical equilibrium shift mechanism involving oleylammonium led to the PL loss and recovery of α-CsPbI PQDs. This chemical equilibrium shift also played an important role in other PQD stabilities against long-term storage, temperature, UV irradiation and ethanol, which were all significantly improved after treatment. The treated α-CsPbI PQDs were phase stable for more than 6 months. Oleic acid and oleylamine are common ligands used in PQD syntheses; this study shall promote the understanding of PQD surface chemistry and the preparation of stable α-CsPbI PQDs.
α-铯铅碘钙钛矿量子点（PQDs）在发红光发光二极管和太阳能电池应用方面具有巨大潜力。然而，它们的不稳定性以及随时间快速的光致发光损失极大地限制了其发展。在本研究中，我们发现经过三辛基膦表面处理后，不发光的老化α-铯铅碘量子点能立即恢复荧光发射。同时，这种表面处理对新鲜的α-铯铅碘量子点也有效，可增强光致发光发射。详细分析了表面处理前后新鲜和老化量子点的结构与组成。我们证明了涉及油胺的表面化学平衡移动机制导致了α-铯铅碘量子点的光致发光损失与恢复。这种化学平衡移动在其他量子点抵抗长期储存、温度、紫外线照射和乙醇的稳定性方面也起着重要作用，处理后这些稳定性都得到了显著改善。处理后的α-铯铅碘量子点在6个多月内保持相稳定。油酸和油胺是量子点合成中常用的配体；本研究将促进对量子点表面化学的理解以及稳定α-铯铅碘量子点的制备。
