PHOTORECEPTOR COMPOSED OF SPIROPYRAN-TCNQ FILMS FOR IMAGE EXTRACTION

A photoreceptor consisting of 6-nitro-spiropyran and TCNQ films was co nstructed. TCNQ Langmuir-Blodgett (LB) films were deposited onto the p retreated quartz substrate and its photoelectric effect was verified. The photocurrent generated by TCNQ was proportional to the light inten sity. The other side of the quartz substrate was deposited by spiropyr an with long alkyl chain using the spin-coating technique. The absorba nce change of the spiropyran films irradiated by UV light was proporti onal to the light intensity on irradiation with green light. The maxim um absorbance change of spiropyran film was observed at 595 nm and the saturation of the absorbance change occurred after 30 min under conti nuous irradiation of UV light. In the constructed photoreceptor, the i ncrement of the intensity ratio of transmitted light in comparison wit h that of input light was obtained when two input lights with the diff erent light intensity were irradiated on the films. Depending on the i ntensity of transmitted light, the photocurrent was generated by TCNQ LB film. By this process, the ratio of output photocurrent generated b y the transmitted light larger than the ratio of input light intensity could be obtained, which can be applied to the construction of the im age sensor to extract the desired image. The extraction efficiency of the proposed photoreceptor was about 10% with 15 min of extraction tim e. (C) 1998 Elsevier Science S.A. All rights reserved.