Electronic interactions in codeposited films of naphthalene tetracarboxylic derivatives and metals

Abstract

Using various spectroscopic techniques, we have investigated the electronic interactions between organic molecules and metals in codeposited films to clarify the properties of the organic/metal interface, and to elucidate the potential of promising organic materials in electronics. Naphthalene tetracarboxylic anhydride codeposited with indium showed marked changes in its electronic absorption and electron spin resonance peaks under atmospheric conditions. X-ray diffraction and infrared absorption measurements revealed that these electronic interactions prevent any aggregation of organic molecules that results in the formation of microscopically mixed and amorphous-like films. From measurements on various combinations of organic molecules and metals, we have concluded that these electronic interactions can be attributed to partial charge transfer from the metal to carbonyl oxygen of the organic molecules.