NOVELTY - The optoelectric transducer (20) consists of a semiconductor film (6) sensitized by lignin derivative(s). The lignin derivative is chosen from lignophenol derivatives, second order and higher order derivatives obtained from lignophenol derivatives, substances consisting of crosslinked second order derivatives, or crosslinked higher order derivatives, which are obtained specifically.    USE - For photoelectrochemical cell (claimed) used at p-n junction of semiconductor crystal or amorphous substrate.    ADVANTAGE - The optoelectric transducer semiconductor thin film electrode is free of carbon resource restraints, and hence does not cause environmental pollution. The optoelectric transducer has high photoelectric conversion efficiency, and is inexpensively manufactured.    DETAILED DESCRIPTION - The optoelectric transducer (20) consists of a semiconductor film (6) sensitized by at least one type of lignin derivative. The lignin derivative is chosen from lignophenol derivatives, second order derivatives obtained from lignophenol derivatives, higher order derivatives obtained from lignophenol derivatives, substances consisting of crosslinked second order derivatives, and substances consisting of crosslinked higher order derivatives. The lignophenol derivative is a phenol compound derivative of lignin obtained by adding an acid and mixing lignin-containing material after dissolving a phenol compound. The secondary derivative and higher order derivative are obtained by performing reaction chosen from acyl-group introduction reaction, carboxyl group introduction reaction, amide-group introduction reaction, crosslinkable group introduction reaction and alkali treatment reaction with respect to lignophenol derivative. The crosslinked component of secondary derivative and higher order derivative, obtained by crosslinkable group introduction reaction, are crosslinked among the secondary derivatives and higher order derivatives, respectively to obtain substances consisting of crosslinked second order derivatives and substances consisting of crosslinked higher order derivatives, respectively. The semiconductor film of optoelectric transducer is preferably sensitized by lignophenol derivative.    INDEPENDENT CLAIMS are included for the following:    (1) manufacture of optoelectric transducer; and    (2) photoelectrochemical cell (40).    DESCRIPTION OF DRAWING(S) - The figure shows the structure of photoelectrochemical cell consisting of optoelectric transducer.    Electroconductive support (4)    Semiconductor film (6)    Optoelectric transducer (20)    Charge transferring layer (22)    Counter electrode (24)    Photoelectrochemical cell (40)