PNNL

Abstract

Numerous chemical and physical methods have been investigated for preparing anatase TiO2 films due to their important electronic, optical and catalytic properties. Among these, chemical methods (sol-gel synthesis1, 2 and solution deposition3) are of particular interest because of the simplicity and wide applicability. However, up to date, chemical synthesis of oriented transparent anatase films with well-defined crystallinity and morphology has not been reported. Literature results strongly suggest that in TiO2 the electrochemical4, 5 and catalytic properties,6 and the energy conversion efficiency in photovoltaics,7 depend on specific surfaces and growth orientation. Even though anatase is catalytically more active, fundamental understanding of the surface chemistry of this important material falls far behind that of the rutile phase due to the difficulty to obtain quality crystals.8 The ability to prepare oriented, well-defined nanocrystalline anatase films would provide new opportunities to study the orientation and structure dependent properties and optimize the device performance.