Detailed studies on the photoswitching property of ferrocene-doped poly(methyl methacrylate) thin films containing chloroform molecules

Electrical conductivity in solution cast (using chloroform as well as mixture of chloroform and benzene as solvents) ferrocene-doped poly(methyl methacrylate) (PMMA) thin films were studied under photoexcitation in air by using surface-type sample cells at room temperature (300 K). The changes in current were measured in the films upon photoexcitation and after turning it off for repeated photoexcitations after a sufficient interval of time. Such studies were carried out as a function of the amount of chloroform in the PMMA film as well as the amount of ferrocene in the film prepared from chloroform. Ferrocene-doped PMMA thin films prepared from solution in chloroform and modified under photoexcitation in air have exhibited interesting photoswitching property monitored by photoconductivity measurements in air. The rise and decay of the photocurrent were studied. The results on photoconductivity have been discussed on the basis of formation of photoinduced charge-transfer complexes of ferrocene with chloroform molecules confined in the PMMA thin films, dissociation of the complexes, secondary thermal reaction and photodegradation of PMMA. Photodegradation of PMMA was studied by FTIR spectroscopy. The possible application of the modified ferrocene-doped PMMA films (containing chloroform molecules) upon photoexcitation in air has been mentioned. (c) 2005 Elsevier B.V. All rights reserved.