Herein, a solution method is used to synthesize lead-free Cs₃Sb₂Br₉ perovskite microplatelets. The freshly prepared microplatelets exhibit photoluminescence (PL) peaks at about 420 and 600 nm, when the excitation wavelengths are 325 and 532 nm, respectively. The 420 nm PL band is attributed to the band edge excitonic recombination while the 600 nm PL band originates from radiative defect state. The 600 nm emission is stronger than that of the 420 nm emission, implying the high density of defects and relatively poor crystal quality. Moreover, 2D PL and Raman mappings indicate the presence of defects at the edges. These features suggest the crystal quality, so as the structural stability of the Cs₃Sb₂Br₉ microplatelets obtained by solution method is relatively inferior. During the storage, the Cs₃Sb₂Br₉ microplatelets significantly degrade and the PL rapidly quenches. To improve the stability, a surface capping strategy by oleic acid (OA) is developed. The PL intensity retains more than 80% and the morphology maintains after storage for about one month, demonstrating the improved stability of the OA-capped Cs₃Sb₂Br₉ microplatelets.

中文翻译：

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溶液法制备无铅 Cs3Sb2Br9 钙钛矿微片的光学性能和稳定性

本文采用溶液法合成无铅Cs ₃ Sb ₂ Br ₉钙钛矿微片。当激发波长分别为 325 和 532 nm 时，新制备的微血小板在约 420 和 600 nm 处表现出光致发光 (PL) 峰。420 nm PL 波段归因于带边激子复合，而 600 nm PL 波段源自辐射缺陷态。600 nm 发射比 420 nm 发射强，意味着缺陷密度高，晶体质量相对较差。此外，2D PL 和拉曼映射表明边缘存在缺陷。这些特征表明晶体质量，以及 Cs ₃ Sb ₂ Br的结构稳定性₉溶液法获得的微血小板相对较差。在储存期间，Cs ₃ Sb ₂ Br ₉微血小板显着降解并且PL迅速淬灭。为了提高稳定性，开发了一种油酸 (OA) 表面封端策略。PL 强度保持超过 80%，形态在储存约 1 个月后保持不变，表明 OA 封端的 Cs ₃ Sb ₂ Br ₉微血小板的稳定性得到改善。