Chen Yameng, Wang Zhaoyu, Wei Youchao, Liu Yongsheng, Hong Maochun
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Angew Chem Int Ed Engl. 2023 Apr 24;62(18):e202301684. doi: 10.1002/anie.202301684. Epub 2023 Mar 22.
Exciton localization is an approach for preparing highly luminescent semiconductors. However, realizing strongly localized excitonic recombination in low-dimensional materials such as two-dimensional (2D) perovskites remains challenging. Herein, we first propose a simple and efficient Sn vacancy (V ) tuning strategy to enhance excitonic localization in 2D (OA) SnI (OA=octylammonium) perovskite nanosheets (PNSs), increasing their photoluminescence quantum yield (PLQY) to ≈64 %, which is among the highest values reported for tin iodide perovskites. Combining experimental with first-principles calculation results, we confirm that the significantly increased PLQY of (OA) SnI PNSs is primarily due to self-trapped excitons with highly localized energy states induced by V . Moreover, this universal strategy can be applied for improving other 2D Sn-based perovskites, thereby paving a new way to fabricate diverse 2D lead-free perovskites with desirable PL properties.
激子局域化是制备高发光半导体的一种方法。然而，在二维（2D）钙钛矿等低维材料中实现强局域化激子复合仍然具有挑战性。在此，我们首次提出一种简单有效的锡空位（V）调控策略，以增强二维（OA）₂SnI₄（OA = 辛基铵）钙钛矿纳米片（PNSs）中的激子局域化，将其光致发光量子产率（PLQY）提高到约64%，这是碘化锡钙钛矿报道的最高值之一。结合实验和第一性原理计算结果，我们证实（OA）₂SnI₄ PNSs的PLQY显著提高主要归因于由V诱导的具有高度局域化能态的自陷激子。此外，这种通用策略可用于改善其他二维锡基钙钛矿，从而为制备具有理想PL特性的各种二维无铅钙钛矿开辟了一条新途径。
