Spray-coated perovskite hemispherical photodetector featuring narrow-band and wide-angle imaging.

Feng, Xiaopeng; He, Yuhong; Qu, Wei; Song, Jinmei; Pan, Wanting; Tan, Mingrui; Yang, Bai; Wei, Haotong · Nat Commun · 2022

basic_science · Level V

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Abstract

Sphere imagers featuring specific wavelength recognition and wide-angle imaging are required to meet the fast development of modern technology. However, it is still challenging to deposit high-quality photosensitive layers on sphere substrates from low-cost solution processes. Here we report spray-coated quasi-two-dimensional phenylethylammonium/formamidinium lead halide (PEA<sub>2</sub>FA<sub>n-1</sub>Pb<sub>n</sub>X<sub>3n+1</sub>) perovskite hemispherical photodetectors. The crystallization speed is manipulated by perovskite compositions, and the film thickness can be controlled by spray-coating cycles and solution concentration from tens of nanometers to hundreds of micrometers with a fast velocity of 1.28 × 10<sup>-4</sup> cm<sup>3</sup> s<sup>-1</sup>. The lens-free hemispherical photodetectors allow light response at a wide incident angle of 180°. Simultaneously, the wavelength selective response from visible to the near-infrared range is achieved with full width at half maximums (FWHMs) of ~20 nm, comparable to single-crystal devices. Wide-angle and wavelength-selective imaging are also demonstrated, which can find potential applications in intelligent recognition and intraoperative navigated surgery.