Berlin 2018 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 13: Poster Session I
HL 13.64: Poster
Monday, March 12, 2018, 17:30–19:30, Poster B
Solution-Based Layers of Nickel Oxide for Applications in Electrochromic Windows — •Florian Eberheim, Christian Lupó, and Derck Schlettwein — IAP, JLU Giessen, Germany
Electrochromic windows are of interest in light-managing devices like smart windows or smart mirrors. The aim of this work consist in the preparation of an electrochromic ion storage anode which is compatible to other device constituents. Nickel oxide can serve for this purpose with properties complementary to tungsten oxide as cathode. Because of the thermal sensitivity of intercalated tungsten oxide layers the production temperature of the nickel oxide layers should be sufficiently low. In this project nickel oxide is produced at 230∘C by an internal combustion reaction with urea as fuel. For this synthesis nickel nitrate hexahydrate, urea and a solvent were mixed. Ethanol, acetone, H2O, methanol, 1-Propanol or DMSO where used as solvents. The nickel oxide layer is made by spin-coating this solution onto the substrate (FTO on glass) and heating on a hot-plate. Non-stoichiometric NiO is formed with a considerable concentration of Ni3+ centers, leading to a dark-brown color. These layers were characterized by SEM and studied by cyclic voltammetry in contact to a Li+-containing organic electrolyte. Upon reduction and Li+-intercalation the layers became widely transparent as desired for compatibility with tungsten oxide. The ion-capacity and the reversibility of this reaction was determined dependent on preparation conditions and film thickness. It was shown that ethanol as solvent led to layers with the highest ion capacity and the largest change in coloration.