Low-dimensional halide perovskite (HP) has triggered lots of research attention in recent years due to anisotropic optoelectronic/semiconducting properties and enhanced stability. High-quality low-dimensional HPs via controllable engineering are required to fulfill the encouraging promise for device applications. Here, we introduce, for the first time, postsynthetic ultrasonic-assisted refinement of two-dimensional homologous HPs (OA2PbBr4, OA is octadecylamine). The solution-prepared OA2PbBr4, either in the form of large-sized microcrystal or nanosheet, obtains significantly enhanced crystallinity after ultrasonic treatment. We further show that OA2PbBr4 nanosheets can be used as a template to construct low-dimensional CsPbBr3 with the size and morphology inherited. Importantly, we found the ultrasonic-treated OA2PbBr4 crystals, compared with pristine ones, lead to enhanced optoelectronic properties for the resultant low-dimensional CsPbBr3, as demonstrated by improved photodetection performances, including prolonged charge-carrier lifetime, improved photostability, increased external quantum yield/responsivity, and faster response speed. We believe this work provides novel engineering of low-dimensional HPs beyond the reach of straightforward synthesis.
Keywords: 2D halide perovskite; dimensionality construction; low-dimensional CsPbBr3; optoelectronic properties; ultrasonic-assisted treatment.