Materials and functional characterisation of AACVD-deposited CuFeO2 photocatalytic thin films

P-type Delafossite CuFeO2 particulate thin films have been synthesized via an aerosol-assisted chemical vapor deposition method on ITO-coated quartz substrates. Through meticulous adjustments in precursors, solvents, and deposition conditions, we achieved remarkable fine-tuning capabilities, enabling precise control over the film's properties. Scanning electron microscope images show changes in film morphology under different synthesis conditions, allowing us to correlate the influence of morphology and thickness on the photocatalytic efficiency, The highest photocurrent density measured in 1M NaOH electrolyte with 10% 0.1 M Na2S2O8 was ~240 μA/cm2 at 0.4 V vs. reversible hydrogen electrode, with an incident photon to charge carrier efficiency of 4.5%. Transient absorption spectroscopy unveiled distinct behaviour of charge carrier dynamics in CuFeO2 films of varying morphology and thickness, ultimately highlighting that superior photoelectrochemical performance in the CuFeO2 film stemmed from the promotion of hole thermalization. Our research unveiled a pivotal relationship between film thickness, morphology and the photoactivity of the CuFeO2 thin films, providing a guide to optimizing performance in CuFeO2 thin film photoelectrodes, and insights for the synthesis of other photoelectrodes.