Controlled Ligand-Free Growth of Free-Standing CsPbBr₃ Perovskite Nanowires

Metal halide perovskite nanowires are widely studied due to their unique electronic and optical characteristics, making them promising for light emitting and detection applications. We developed a ligand-free method to grow vertically aligned free-standing CsPbBr₃ nanowires from anodized aluminum oxide nanopore substrates. Here, we investigate the growth process using in situ microscopy with ultraviolet and visible light excitation, revealing a highly dynamic process with pronounced fluorescence at locations where high-density free-standing nanowires could be found. The yield of the growth is strongly improved by using a growth reactor with controlled N₂ flow, increasing from 17 to 60%. We systematically investigated the growth dependence on the temperature and N₂ flow rate and identified optimal parameters at 70 °C and 0.8 L/min, respectively. The improved control over the growth of free-standing nanowires expands opportunities for their integration into optoelectronic devices.