The development of new methods to engineer lead halide perovskite crystals with a controlled band gap and emission properties is an active subject in materials science and chemistry. We present the preparation of mixed-halide lead perovskites by spatially- and temporally- controlled chemical reactions and crystal growth under an optical potential in unsaturated precursor solutions. The crystals are characterized by transmission and photoluminescence spectral measurements and X-ray diffraction analysis. When compared with the spontaneous formation of multiple crystals in saturated precursor solutions, the optical potential creates large single crystals with a high chloride composition, providing distinct blue and green fluorescent crystals of chloride–bromide lead perovskites. We discuss the formation of mixed-halide perovskites from the viewpoints of an increased rate of chemical reaction via the formation and desolvation of precursor complexes and a decreased free energy potential.

在材料科学和化学领域，开发可控制带隙和发射特性的工程化卤化钙钛矿铅晶体的新方法是一个活跃的课题。我们目前通过空间和时间控制的化学反应和在不饱和前体溶液中的光势下的晶体生长来制备混合卤化物钙钛矿。晶体的特征在于透射和光致发光光谱测量以及X射线衍射分析。与饱和前体溶液中自发形成的多晶体相比，光势可以生成具有高氯化物组成的大单晶，从而提供氯化物-溴化铅钙钛矿的独特蓝色和绿色荧光晶体。通过前体复合物的形成和去溶剂化以及降低的自由能势。