Lattice atom-bridged chemical bond interface facilitates charge transfer for boosted photoelectric response

The construction of chemical bonds at heterojunction interfaces currently presents a promising avenue for enhancing photogenerated carrier interfacial transfer. However, the deliberate modulation of these interfacial chemical bonds remains a significant challenge. In this study, we successfully established a p-n junction composed of atomic-level Pt-doped CeO₂ and 2D metalloporphyrins metal-organic framework nanosheets (Pt-CeO₂/CuTCPP(Fe)), which enables the realization of photoelectric enhancement by regulating the interfacial Fe-O bond and optimizing the built-in electric field. Atomic-level Pt doping in CeO₂ leads to an increased density of oxygen vacancies and lattice mutation, which induces a transition in interfacial Fe-O bonds from adsorbed oxygen (Fe-O_A) to lattice oxygen (Fe-O_L). This transition changes the interfacial charge flow pathway from Fe-O_A-Ce to Fe-O_L, effectively reducing the carrier transport distance along the atomic-level charge transport highway. This results in a 2.5-fold enhancement in photoelectric performance compared with the CeO₂/CuTCPP(Fe). Furthermore, leveraging the peroxidase-like activity of the p-n junction, we employed this functional heterojunction interface to develop a photoelectrochemical immunoassay for the sensitive detection of prostate-specific antigens.