Surface-guided Halide Perovskite Nanowires: New Building Blocks with Unusual Properties for Optoelectronics

Metal-halide perovskites (MHPs) are remarkable optoelectronic materials due to a rare combination of low-cost fabrication and exceptional properties. Recently, nanowires of MHPs have emerged as promising building blocks for various optoelectronic application and as an intriguing one-dimensional system for investigating and modeling fundamental MHPs properties. Both for research and applications, controlled and well-defined nanowire systems are highly advantageous, and at times a real necessity. Here we employ a surface-guided approach to grow horizontally aligned arrays of single-crystal CsPbBr₃ nanowires. The nanowires grow with well-defined facets and a uniform crystallographic orientation to form aligned arrays with 6-fold and 2-fold symmetries. We highlight the advantages of such arrays for fundamental research, as we investigate their optical properties, and present a unique perspective on photon-transport processes and anomalous diameter-dependent emission shift. In addition, we demonstrate the potential of planar MHPs nanowires as building blocks for functional devices by fabricating photodetectors that exhibit faster response times than any CsPbBr₃-based photodetectors reported so far. Arrays of horizontally aligned MHPs nanowires are a promising platform for investigating the intriguing properties and potential applications of these unique materials.