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

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(2)FA(n-1)Pb(n)X(3n+1)) 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 x 10(-4) cm(3) s(-1). The lens-free hemispherical photodetectors allow light response at a wide incident angle of 180 degrees. Simultaneously, the wavelength selective response from visible to the near-infrared range is achieved with full width at half maximums (FWHMs) of similar to 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.

Automated summary

In this study, spray-coated quasi-2D hemispherical photodetectors based on phenylethylammonium/formamidinium lead halide perovskites were reported. The crystallization speed and film thickness were controlled by perovskite compositions and spray-coating cycles. The resulting photodetectors showed wide-angle light response and wavelength-selective imaging, with potential applications in intelligent recognition and intraoperative navigated surgery.