Polarization-modulated programmable photovoltaic performance of a designed ferroelectric heterojunction.

Conventional photovoltaic devices based on PN or Schottky junctions are inherently constrained by the material band gap, resulting in limited photoelectric conversion efficiency. The van der Waals ferroelectric material CuInP2S6 offers strong potential for efficient photocurrent generation via bulk photovoltaic effect, while heterostructure engineering provides additional degrees of freedom for performance modulation. Yet, the specificity in asymmetric CuInP2S6 heterojunctions remains poorly understood. Here, we design and fabricate an asymmetric photovoltaic device, consisting of Pt/CuInP2S6/Graphene heterostructure. The ferroelectric photovoltaic effect couples with the Cu+ migration dynamics, which could be manipulated by asymmetric interface barriers. Remarkably, the photovoltaic current is increased by 10 times and exhibits a positive-negative switching through polarization modulation. The heterojunction device achieves on-demand photovoltaic programming for in-sensor computing tasks, including edge detection with recognition rate F-score ~ 1 and binary pattern classification with 100% accuracy, which provides new insights for next-generation visual technology.