Molecular photoreceptor consisting of bacteriorhodopsin/flavin complex Langmuir-Blodgett films

A dual-band photoreceptor composed of bacteriorhodopsin (bR)/flavin complex Langmuir-Blodgett (LB) films was constructed. Molecular thin films were deposited by aligning bR and flavin onto ITO glass using the LB technique. The absorption spectrum of bR/flavin complex LB films was measured to confirm the deposition of bR and flavin onto the single substrate. The photoreceptor was fabricated by setting the bR/flavin complex LB films deposited onto ITO glass into an electrochemistry cell. Two light sources, 400 nm for flavin and 550 nm for bR, were used for the photocurrent generation. The properties of the device as a dual-band photoreceptor could be successfully verified based on the photocurrents of bR and flavin generated from the single photoreceptor. The action spectrum obtained by the series of irradiation of a single light source was fairly well consistent with the absorption spectrum of the bR/flavin complex LB films, and two action peaks at around 400 nm and 550 nm existed. Based on the action spectrum, it was concluded that almost all visible light (400 similar to 650 nm) can be detected by the proposed dual-band photoreceptor, and its properties can be extended to the possible application as a light spectrum analysis for colour recognition of visible light. (C) 1998 Elsevier Science S.A. All rights reserved.