X-ray photoelectron spectroscopy and luminescent properties of Y2O3:Bi3+ phosphor

•XPS results for high Bi concentration indicated the Bi 4f peaks inside the Y 3d energy range.•XPS also indicated the C2 and S6 sites in both Y2O3 and Bi2O3 that results in blue and green luminescence centers.•The false-color CL overlay results also proved the emission of the Bi3+ ion in the two different sites. X-ray photoelectron spectroscopy (XPS) results provided proof for the blue and green emission of Bi3+ in the Y2O3:Bi3+ phosphor. The Y2O3:Bi3+ phosphor was successfully prepared by the combustion process during the investigation of down-conversion materials for Si solar cell application. The X-ray diffraction (XRD) patterns indicated that a single-phase cubic crystal structure with the Ia3 space group was formed. X-ray photoelectron spectroscopy (XPS) showed that the Bi3+ ion replaces the Y3+ ion in two different coordination sites in the Y2O3 crystal structure. The O 1s peak shows five peaks, two which correlate with the O2− ion in Y2O3 in the two different sites, two which correlate with O2− in Bi2O3 in the two different sites and the remaining peak relates to hydroxide. The Y 3d spectrum shows two peaks for the Y3+ ion in the Y2O3 structure in two different sites and the Bi 4f spectrum shows the Bi3+ ion in the two different sites in Bi2O3. The photoluminescence (PL) results showed three broad emission bands in the blue and green regions under ultraviolet excitation, which were also present for panchromatic cathodoluminescence (CL) results. These three peaks have maxima at ∼3.4, 3.0 and 2.5eV. The PL emission ∼3.0eV (blue emission) showed two excitation bands centered at ∼3.7 and 3.4eV while the PL emission at ∼2.5eV (green emission) showed a broad excitation band from ∼4 to 3.4eV. The panchromatic CL images were obtained for selected wavelengths at (2.99±0.08)eV (for blue emission) and (2.34±0.06)eV (for green emission). These luminescence results correlate with the XPS results that show that there are two different Bi3+ sites in the host lattice.