OPTICAL CO DETECTION BY USE OF CUO AU COMPOSITE FILMS/

Composite films consisting of a thin CuO layer and ultrafine Au partic les have been found to be usable for the optical detection of CO in ai r. The optical absorption of CuO/Au composite films increases due to C O and recovers reversibly in air free of CO. The largest absorbance ch ange due to CO is in the 700-800 nm wavelength region, with the absorb ance change enhanced by increasing temperature or increasing CO concen tration. We assume that the absorbance change of the CuO/Au film occur s due to the change in the electronic structure of the ultrafine Au pa rticles as a result of their interactions with atmospheric gas.