Quaternary CsPbX₃ (X = Cl_1−xBr_x, Br_1−xI_x) alloy microplates synthesized by single-step chemical vapor deposition and their two-photon absorption (TPA) properties

Because of their well-defined light-matter interaction volume, high-quality single-crystalline nature, and precise bandgap tunability, all-inorganic cesium lead halide (CsPbX₃ (X = Cl, Br, I)) perovskite (IHP) microplates are of fundamental and technological interest today. Here, we report the synthesis and properties of ternary CsPbX₃ (X = Cl, Br, I) and quaternary CsPbX₃ (X = Cl_1−xBr_x, Br_1−xI_x) alloy microplates grown by the single-step chemical vapor deposition (CVD) process. Smooth-faceted, single crystalline IHP alloy microplates with good vertical and lateral composition uniformity are achieved. These microplates exhibit strong photoluminescence and are thermally stable with no observable photodegradation. More importantly, two-photon absorption (TPA) is demonstrated in quaternary CsPb(Cl_1−xBr_x)₃ and CsPb(Br_1−xI_x)₃ IHP alloy microplates, which adds a new dimension to the functionalities of IHP microplates for nonlinear optical (NLO) applications. We believe that this work will open up multiple avenues for the development of microstructure compatible integrated optoelectronic and photonic applications and will certainly enhance the fundamental NLO research.