Ultranarrow-band filterless photodetectors based on CH3NH3PbClxBr3-x mixed-halide perovskite single crystals.

Narrow-band photodetectors based on halide perovskite have recently attracted significant attention due to their exceptional narrow-band detection performance and tunable absorption peaks covering a wide optical range. In this work, we report mixed-halide CH3NH3PbClxBr3-x single crystal-based photodetectors have been fabricated, where the Cl/Br ratios were varied (3:0, 10:1, 5:1, 1:1, 1:7, 1:14 and 0:3). Three different structures of devices were constructed by changing the connection of electrodes and the direction of light illumination. Both the vertical and parallel structure devices with bottom illumination exhibited ultranarrow spectral responses, with a full-width at half-maximum less than 16 nm. The observed performance can be ascribed to the unique carrier generation and extraction mechanisms within the single crystal under short and long wavelength of illumination. These findings offer valuable insights into the development of narrow-band photodetectors that do not necessitate the use of filters and hold tremendous potential for a diverse array of applications.