Bioelectronic device based on photoinduced electron transfer such as the biomolecular photodiode consisting of protein-adsorbed hetero film was investigated. Three kinds of functional molecules in biomolecular photodiode were used as a sensitizer, a first electron acceptor, and a second electron acceptor. The hetero-film was fabricated subsequently depositing functional molecules onto the pretreated conducting substrate using self-assembly method and Langmuir-Blodgett film method. The metal/insulator/metal structured bioelectronic device was constructed by depositing the metallic electrode onto the surface of the hetero-films. Based on the photoelectric response properties, the rectifying property in the current-voltage characteristic and the photoswitching effect of the proposed bioelectronic device were observed. The charge separation of molecular interface was verified in time-resolved. fluorescent measurement by the time-correlated single photon counting method. The charge shift in the device was analyzed by the measurement of transient photocurrent of the device and thus the efficient directional flow of photocurrent through the redox potential difference was observed. (C) 2002 Published by Elsevier Science B.V.