High-definition colorful perovskite narrowband photodetector array enabled by laser-direct-writing

Narrowband photodetectors as specific spectral sensing pixels have drawn intense attention in multispectral detection due to their distinct characteristic of filter-free spectrum discrimination, in which the emerging halide lead perovskites witness a booming development in their performance and wavelength-selectivity from blue to near-infrared light. However, the challenge in integrating perovskite narrowband photodetectors on one chip imposes an impediment on practical application. In this work, the combination of laser-direct-writing and ion exchange is proposed as an efficient way to fabricate high-definition colorful sensing array with perovskite narrowband photodetector unit as pixel. Under laser irradiation, the photolysis of halocarbon solvent (CHCl₃, CH₃CH₂I, etc) releases the halide ions, which brings the ion exchange and gives rise to slow-varying bandgap in single perovskite photoactive film. This ion exchange can be controlled via laser irradiation time and focus point, thus enabling precisely engineerable bandgap. By optimizing the process, it is successfully applied to develop patterned perovskite narrow blue and green photodetectors array with a high-definition of ~ 53 ppi. We believe this result will make a great step forward to integrate multifunctional perovskite devices on one chip, which will pave the way for perovskite optoelectronic device to the commercial application.