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

. 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.