Vertically Aligned CsPbBr Nanowire Arrays with Template-Induced Crystal Phase Transition and Stability.

Metal halide perovskites show great promise for a wide range of optoelectronic applications but are plagued by instability when exposed to air and light. This work presents low-temperature solution growth of vertically aligned CsPbBr nanowire arrays in AAO (anodized aluminum oxide) templates with excellent stability, with samples exposed to air for 4 months still exhibiting comparable photoluminescence and UV stability to fresh samples. The single-crystal nanowire length is adjusted from ∼100 nm to 5 μm by adjusting the precursor solution amount and concentration, and we observe length-to-diameter ratios as high as 100.

Origin of Ionic Inhomogeneity in MAPb(IBr) Perovskite Thin Films Revealed by In-Situ Spectroscopy during Spin Coating and Annealing.

Irradiation-induced phase segregation in mixed methylammonium halide perovskite samples such as methylammonium lead bromide-iodide, MAPb(IBr), is being studied intensively because it limits the efficiency of wide band gap perovskite solar cells. It has been postulated that this phenomenon depends on the intrinsic ionic (in)homogeneity in samples already induced during film formation. A deeper understanding of the MAPb(IBr) formation processes and the influence of the halide ratio, solvents, and the perovskite precursor composition as well as the influence of processing parameters during deposition, e.