Ultrafast Response and Broad Detection Range of a Ternary Cation Perovskite Single-Crystal Thin Film Photodetector for Imaging.

ABSTRACT

FA-MA-Cs ternary cation perovskite exhibits excellent optoelectronic properties and high stabilities against humidity and light soaking and thus has aroused extensive attention in polycrystalline thin film solar cells. Compared with polycrystalline counterparts, FA-MA-Cs ternary cation perovskite single-crystal thin films (SCTFs) have lower defects, better carrier transport capacity, and stability because of lacking grain boundary defects. However, the immature growth technology of SCTFs restricts digging out its optoelectronic potential. Here, we proposed an improved space-confined method to grow large area FA0.9 MA0.05Cs0.05PbI2.7Br0.3 SCTFs using a tunable heating area to control the nucleation and growth process. Its area reaches 64 mm2 with a thickness of 26 µm. The SCTF exhibits high crystallinity, low defect density, long carrier lifetime, and high moisture resistance stability. Besides, a photosensitive chip based on a planar metal-semiconductor-metal photodetector demonstrates linear response to the three primary colors, with a photosensitive range that is 1.5 times that of protocol 3 wide color gamut. Under high-frequency light sources, the on/off ratio reaches 3.9 × 103, and the response time can be as low as 400 ns. Such ultrafast response speed and broad photosensitive range are successfully achieved for imaging applications.