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

Abstract

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.

Propylammonium Chloride Additive for Efficient and Stable FAPbI3 Perovskite Solar Cells

“…Besides, the most intense scattering signal at the meridian (100) peak of out of plane (q xy = 0 Å -1 and q z = 1 Å -1 ) is observed, which implies the preferential crystal orientations for α phase FAPbI 3 in PACl additive perovskite film. [37,38] Thus, our results demonstrate that the addition of PACl stabilizes the α-phase FAPbI 3 with enhanced crystallinity and preferential crystal orientation of the (100) plane normal to the substrate. It is found from the top-view scanning electron microscope (SEM) images in Figure 2e,f that the control FAPbI 3 perovskite has grains comprising large number of small grains and wrinkles, while the small grains are eliminate and smooth large grains are formed in the perovskite film with PACl addition.…”

Nanochannel-confined growth of crystallographically orientated perovskite nanowire arrays for polarization-sensitive photodetector application

“…3a-f) and XRD patterns (Fig. S5) confirm that the as-obtained samples are all composed of well-aligned PNW arrays with good crystallinity and preferential crystallographic orientation [20,[36][37][38]. Significantly, the PNW arrays can also be grown on other rigid and flexible substrates including glass, PP and PET, as long as these substrates are hydrophilic after surface treatment.…”

High‐Stability Patterned CsPbIxBr3−x Thin Films with Tunable Crystal Size Prepared by Solid‐Phase Reaction

“…For the four devices, the responsivity (R) can be calculated by R = (I light -I dark )/P, where I light is the current under light illumination, I dark is dark current and P is illumination power. [44] As calculated, their responsivity at 2.5 V can reach 1. The surface coverage of thin films grown by PLD technology is high, as obvious from the SEM images.…”