Interface Engineering of π-Conjugated Conducting Metal–Organic Frameworks for Multiband Self-Powered Photodetector

Highly two-dimensional π-conjugated metal-organic framework (MOFs) films have attracted significant attention in optoelectronics due to their excellent charge transport properties, strong light absorption, and tunable molecular structures. Compared with conventional inorganic two-dimensional materials, π-conjugated MOF offer greater structural diversity, enhanced optical absorption, and more tunable charge transport pathways, all of which contribute to improved photoelectric conversion efficiency and overall device performance. However, the generation of photocurrent in two-dimensional π-conjugated MOFs is challenging due to their short carrier lifetime. Expanding the application of MOFs films in the field of optoelectronics is therefore worth exploring. In this study, a π-conjugated conductive Ni3(HITP)2 film was prepared using an air-liquid interface growth method and integrated with n-Si to fabricate a p-n junction self-powered photodetector. The built-in electric field of the p-n junction was used to extend the carrier lifetime, while the broadband high absorption of Ni3(HITP)2 was utilized to broaden the operating range of the silicon-based detector. This photodetector exhibits ultrahigh speed (rise time of 5.9 μs, fall time of 64 μs), high responsivity (0.618 A/W), and high quantum efficiency (94%). Additionally, theoretical calculations revealed a low barrier between Ni3(HITP)2 and n-Si, contributing to the device's fast response. This study presents a new approach to high-performance π-conjugated MOFs hybrid optoelectronics through the development of Ni3(HITP)2-based photodetectors.