Electronic and optical properties of Er-doped Y2O2S phosphorsElectronic supplementary information (ESI) available: Absorption spectra, emission spectra of Y2O2S:1%Er3+ in the range of 350 to 850 nm under UV excitations, emission spectra of Y2O2S:x%Er3+ (x = 7 and 10) in the range of 350 to 850 nm under UV excitations, QY measurements, decay measurement fitting. See DOI: 10.1039/c5tc02665b

• Main Authors: Pokhrel, M, Kumar, G. A, Ma, C.-G, Brik, M. G, Langloss, Brian W, Stanton, Ian N, Therien, Michael J, Sardar, D. K, Mao, Yuanbing
• Format: Article
• Language: English
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c5tc02665b

In this paper, we report a detailed computational and experimental investigation of the structural, electronic and dynamic properties of undoped and Er 3+ -doped Y 2 O 2 S phosphors by using computational crystal field (CF) calculations and electronic density of states by density functional theory (DFT), combined with optical measurements including excitation spectra, emission spectra from X-ray, ultraviolet and near infrared (NIR) excitations, and quantum yield determination under ultraviolet and NIR excitations. Emission decays and quantum yields of the visible and NIR bands were measured for different Er 3+ doping concentrations in the Er 3+ -doped Y 2 O 2 S phosphors. Results show that green (550 nm) and red (667 nm) emission intensity and the respective ratio of these emission intensities depend on both the excitation wavelength and the Er 3+ doping concentration. Although the total emission efficiency does not appreciably depend on the excitation wavelength, the excitation wavelength that provided the highest efficiency was found to be 250 nm in these Er 3+ -doped Y 2 O 2 S phosphors with both 1% and 10% Er doping concentrations. Green light emitted from Y 2 O 2 S:1%Er phosphors after excited with NIR, UV and X-ray sources with emissions spectra under UV and NIR excitations (lower right) and X-ray excitation at different X-ray tube voltages (lower left).