Abstract:
Metal oxide thin-film materials are ubiquitous in several devices and catalytic systems. However, methods amenable to large-scale processing, using low temperatures compatible with organic materials, are scarce. A perceived challenge with low-temperature method is that amorphous materials are obtained, which renders lesser-quality materials. In this talk I will present a photochemical method that affords amorphous metal-oxides with well-controlled composition. Our recent work has focused on characterizing these materials with synchrotron-based techniques, to better understand their short-range structure (at the nanoscale). A surprising behaviour has emerged, which appears to be more prevalent than hitherto appreciated: when annealed, these amorphous materials undergo amorphous-to-amorphous phase transitions which drastically alter their properties. Two families of materials will be discussed: a-(Fe,Ni)Ox and a-RuOx with applications in catalysing the oxygen-evolution reaction during water electrolysis, and a-CuOx and a-VOx, used as hole-transport layers in organic photovoltaics and light-emitting devices.