Photodetector

Metallurgy

Materials science

Orientation (vector space)

Nanocrystalline material

Responsivity

Perovskite (structure)

Photoluminescence

Grain boundary

Nanowire

Grain size

Nanotechnology

Crystallite

Mathematics

Dewetting

Microstructure

Thin film

Geometry

Composite material

Crystallography

Chemistry

Crystallinity

Optoelectronics

Advanced Functional Materials

All‐inorganic metal‐halide perovskites CsPbX 3 (X = Cl, Br, I) exhibit higher stability than their organic–inorganic hybrid counterparts, but the thermodynamically instable perovskite α phase at room temperature of CsPbI 3 restricts the practical optoelectronic applications. Although the stabilization of α‐CsPbI 3 polycrystalline thin films is extensively studied, the creation of highly crystalline micro/nanostructures of α‐CsPbI 3 with large grain size and suppressed grain boundary remains challenging, which impedes the implementations of α‐CsPbI 3 for lateral devices, such as photoconductor‐type photodetectors. In this work, stable α‐CsPbI 3 perovskite nanowire arrays are demonstrated with large grain size, high crystallinity, regulated alignment, and position by controlling the dewetting dynamics of precursor solution on an asymmetric‐wettability topographical template. The correlation between the higher photoluminescence (PL) intensity and longer PL lifetime indicates the nanowires exhibit stable α phase and suppressed trap density. The preferential (100) orientation is characterized by discrete diffraction spots in grazing incidence wide‐angle scattering patterns, suggesting the long‐range crystallographic order of these nanowires. Based on these high‐quality nanowire arrays, highly sensitive photodetectors are realized with a responsivity of 1294 A W −1 and long‐term stability with 90% performance retention after 30‐day ambient storage.

Stable α‐CsPbI<sub>3</sub> Perovskite Nanowire Arrays with Preferential Crystallographic Orientation for Highly Sensitive Photodetectors

Stable α‐CsPbI3 Perovskite Nanowire Arrays with Preferential Crystallographic Orientation for Highly Sensitive Photodetectors

Stable α‐CsPbI₃ Perovskite Nanowire Arrays with Preferential Crystallographic Orientation for Highly Sensitive Photodetectors