State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China.
Phys Chem Chem Phys. 2019 Oct 9;21(39):21996-22001. doi: 10.1039/c9cp04033a.
Solution-processed all-inorganic CsPbX3(X = Br, I, and Cl) perovskites are proven to be promising materials for various optoelectronic applications. However, CsPbX3 films as optical gain media were confronted with unsatisfactory surface coverage and inferior photoluminescence performance when compared with their colloidal nanocrystal counterparts. Herein, we demonstrate a strategy for improving the optical properties via modification of both top and bottom surfaces of CsPbBr3 films. The treated perovskite films show ultra-smooth morphology and a carrier lifetime of 44 ns, more than one order of magnitude longer than the untreated one. Meanwhile, a mixed polymer layer on the top of the perovskite film could combine surface passivation with symmetric waveguide effects, leading to an outstanding net gain coefficient of 694 cm-1. These merits predict the great potential of all-inorganic perovskite films to support high efficiency charge transport or stimulated emission.
溶液处理的全无机 CsPbX3（X = Br、I 和 Cl）钙钛矿已被证明是各种光电应用的有前途的材料。然而，与胶体纳米晶体相比，CsPbX3 薄膜作为光学增益介质，其表面覆盖度不理想，光致发光性能较差。在此，我们展示了一种通过修饰 CsPbBr3 薄膜的顶表面和底表面来改善光学性能的策略。处理后的钙钛矿薄膜具有超光滑的形态和载流子寿命为 44 ns，比未处理的薄膜长一个数量级以上。同时，钙钛矿薄膜顶部的混合聚合物层可以将表面钝化与对称波导效应结合起来，导致出色的净增益系数为 694 cm-1。这些优点预示着全无机钙钛矿薄膜在支持高效电荷输运或受激发射方面具有巨大潜力。
