Structural, optoelectronic and photo-thermoelectric properties of crystalline alloy CuAlxFe1-xO2 delafossite oxide materials

CuFeO2 and CuAlO2 are attractive candidate materials for solar energy harvesting applications such as photocatalysis and photovoltaics. This work describes the structural, optoelectronic, thermal and electric properties of alloyed CuAlxFe1-xO2 Delafossite material synthesized using solid-state sintering techniques. The alloyed samples of CuAlxFe1-xO2 Delafossite oxide consisted of substitution of Fe for Al ranging from x = 0.01 to x = 0.99. The inclusion of Al in low concentrations affects the crystallization rate during solid-state synthesis, dramatically changing the resultant sample morphologies. The addition of dilute amounts of Al also greatly improves the conductivity of the material to a maximum of 3.18 Scm−1. The material absorption edge shows strong changes over the alloying range. The more highly conducting samples show a strong photoinduced thermoelectric response to Vis-NIR illumination. •The concentration of Al drastically effects the sample morphology for the solid-state reaction to form CuAlxFe1-xO2.•The addition of Al to CuFeO2 host greatly improves samples conductivity.•The optical absorbance properties show distinct changes particularly for dilute amounts of Fe.•Near room temperature heat sensitivity of the samples leads to photoinduced thermoelectric currents.