Blueshift in near-band-edge emission in Y^3+-doped CuAlO_2 nanofibers

The optical properties of CuAlO2:Y3+ electrospun nanofibers have been studied through UV-VIS transmittance/reflectance and photoluminescence. A blueshift of the PL spectra was identified for the samples with decreased crystallite sizes and increased doping levels. Analysis of the samples with a quantum size model showed discrepancies resulting from the Y3+ doping, indicating a further band-gap enhancement due to the change in hybridization between the 3dz2 and 4s orbitals in the CuMO2 delafossite. The comparative investigation between size effect estimation and the nominal band-gap enhancement could benefit future research on trivalent doping and violet emission tuning.