Non-dissipative internal optical filtering with solution-grown perovskite single crystals for full-colour imaging

Herein we demonstrate that solution-grown single crystals of semiconducting methylammonium lead halide perovskites (MAPbX(3), where MA=CH3NH3+, X=Cl-, Br- and Br/I-) can be used as semiconductor absorbers for full-colour imaging. A one-pixel photodetector prototype was constructed by stacking three layers of blue-, green-and red-sensitive MAPbCl(3), MAPbBr(3) and MAPb(Br/I)(3) crystals, respectively. The prototype detector was demonstrated to recognize and faithfully reproduce coloured images by recombination of the signals from each individual colour channel. This layered structure concept, besides imparting a two-to three-fold reduction in the number of required pixels, also offers several other advantages over conventional technologies: three times more efficient light utilization (and thus higher sensitivity) than common Bayer scheme devices based on dissipative optical filters, colour moire suppression and no need for de-mosaic image processing. In addition, the direct band gap structure of perovskites results in optical absorption that is several orders of magnitude greater than silicon. This opens a promising avenue towards the reduction of pixel-size in next-generation devices as compared with conventional silicon-based technologies.