Self‐Patterned CsPbBr₃ Nanocrystal Based Plasmonic Hot‐Carrier Photodetector at Telecommunications Wavelengths

Abstract Extending the photodetection range of lead halide perovskites into the near‐infrared telecommunications bands can not only enable a wide‐spectrum solar energy harvesting, but pave ways for important applications in biodetection, infrared imaging, and telecommunication. However, there is a lack of an effective means to apply lead halide perovskites for efficient photodetection covering a wide wavelength range in the telecommunications bands. Here, CsPbBr₃ nanocrystal‐ (NC‐) based photodetector operating at wavelengths in the telecommunications bands via surface plasmon‐induced hot holes is demonstrated. The internal photoemission of the plasmon‐induced hot holes from plasmonic antennas into CsPbBr₃ NCs enables a photocurrent at wavelengths around 1550 nm. Moreover, a solvent treatment is also performed on drop‐casted CsPbBr₃ NC thin film leading to a nanoscale self‐patterning with a compact and uniform morphology. This treatment benefits the carrier transportation contributing to a detectable photoresponse and minimizes the optical scattering so that the CsPbBr₃ NCs can be integrated into the plasmonic structure without damping its resonant feature. Consequently, the CsPbBr₃ NC‐based plasmonic hot‐carrier device achieves polarization discrimination and wavelength‐selective photodetection without additional optical components.