Anodization assisted preparation of diverse nanostructured copper oxide films for solar selective absorber

Copper oxide films with diverse morphologies are prepared on copper (Cu) substrate by anodization method. The concentration of aqueous NaOH solution used as electrolyte during the anodization process is found as crucial towards formation of different nanostructured films. The reaction temperature impact on chemical composition and morphology of films is also determined. X-ray diffraction patterns disclose that CuO and Cu2O are presented in films and the share between both could be altered by changing the NaOH concentration and applied potential. Scanning electron microscopy images unveiled formation of films with diverse morphologies comprised of nanorods, nanoflakes, nanoparticles, and nanoleaves. Raman spectra confirmed the presence of CuO mode and its significant peak intensity has indicated high crystallinity. The prepared films have displayed high solar absorptance (63.5%-77.3%), low thermal emittance (4.5%-5.5%), and better solar selectivity (>14). These re-sults suggest that the anodization method can be employed as a potential technique to prepare facile and affordable solar selective absorbers.

Automated summary

Copper oxide films of different morphologies were successfully prepared on copper substrates using the anodization method. The concentration of the NaOH solution used during the anodization process was found to be crucial in determining the nanostructured films formed. The films exhibited a mixture of CuO and Cu2O phases, with their proportions adjustable through changes in NaOH concentration and applied potential. The prepared films showed high solar absorptance, low thermal emittance, and superior solar selectivity, making the anodization method a promising technique for the fabrication of affordable solar selective absorbers.