Investigation of the effect of ytterbium doping on photoluminescence and photocatalytic activity of Li4Ti5O12

This work reports the combined effect of the morphology and crystallization to investigate the role of Yb³⁺ as an additive in Li₄Ti₅O₁₂ crystals on its photocatalytic and photoluminescence (PL) properties. With the pure phase, the synthesized samples have a spherical morphology and spherical structure with good crystallinity and uniform particle size distribution. Li₄Ti₅O₁₂ doped with ytterbium (Yb³⁺), were obtained by a new optimized hydrothermal approach. The crystal properties and surface morphology of the synthesized compounds were examined by X-ray diffraction method and field emission scanning electron microscopy. Bond structures and surface areas were investigated by Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller analyses. Finally, the excitation and emission spectra were obtained by a PL spectrophotometer. The PL results show that room-temperature PL of Yb³⁺ doped Li₄Ti₅O₁₂ phosphor has an emission peak at 710 nm which can be attributed to Li₄Ti₅O12 crystal defect emission. Moreover, it has been found that Yb doping resulted in enhancement of photocatalytic activity, evaluated by monitoring the degradation of methylene blue solution. Note that, 0.01% Yb doped lithium titania phosphor exhibited excellent photocatalytic activity.