The valence band structure of p-type transparent oxides-crystalline Mg x Cr 2−x O 3 and nanocrystalline Cu x CrO y -is analyzed as a function of incoming photon energy. The valence band of both p-type transparent conducting oxides shows striking similarities to measurements on crystalline CuCrO 2 :Mg with all films showing that chromium states compose the top of the valence band, suggesting that the valence-band structure is dominated by the presence of the Cr-O 6 octahedra. A comparison of the valence band between the best performing p-type, crystalline CuCrO 2 :Mg, with crystalline Mg x Cr 2−x O 3 and nanocrystalline Cu x CrO y shows that the chromium 3d states are fixed irrespective of changes in long-range crystallographic order. This indicates little spatial overlap between adjacent Cr 3d states. This further confirms the conduction mechanism via hopping for chromium based p-type TCOs as the Cr 3d states are localized within the Cr-O 6 octahedra.

abNitrogen-doped Pyrolytic Carbon (N-PyC) films were employed as an electrode material in electrochemical applications. PyC was grown by via non-catalysed chemical vapour deposition and subsequently functionalised via exposure to ammonia-hydrogen plasma. The electrochemical properties of the N-PyC films were investigated using the ferri/ferro-cyanide and hexaamine ruthenium(III) chloride redox probes.Exceptional electron transfer properties were observed and quantified for the N-PyC compared to the as-grown films. X-ray photoelectron spectroscopy confirmed the presence of nitrogen in edge plane graphitic configurations and the surface of the N-PyC was investigated using scanning electron microscopy and atomic force microscopy. The excellent electrochemical performance of the N-PyC, in addition to its ease of preparation, renders this material ideal for applications in electrochemical sensing.