Patent ID: 8092670

Claim:
A method for specifically detecting an analyte, comprising the steps of: contacting a working electrode and a counter electrode with an electrolyte medium, the working electrode having an analyte immobilized thereon through a probe substance, the analyte being bonded to a sensitizing dye; irradiating the working electrode with light to photoexcite the sensitizing dye; and detecting photocurrent flowing between the working electrode and the counter electrode, the photocurrent being generated by transfer of electrons from the photoexcited sensitizing dye to the working electrode; wherein the working electrode comprises an electron accepting layer comprising an electron accepting substance capable of accepting electrons released from the sensitizing dye in response to photoexcitation, the probe substance being supported on a surface of the electron accepting layer; wherein the electron accepting substance is an oxide semiconductor having an energy level lower than that of a lowest unoccupied molecular orbit (LUMO) of the sensitizing dye; wherein the electrolyte medium comprises an electrolyte and at least one solvent selected from an aprotic solvent and a protic solvent, the electrolyte comprising a salt capable of providing an oxidized sensitizing dye with electrons; and wherein the electrolyte is at least one selected from the group consisting of tetraalkylammonium iodide, Br 2 -free bromide, thiosulfate, and sulfite.