Yb
3+/Er
3+codoped La
10W
22O
81 (LWO) nanophosphor rods have been successfully synthesized by a facile hydrothermal assisted solid state reaction method, and their upconversion photoluminescence properties were systematically studied. X-ray diffraction patterns revealed that the nanophosphors have an orthorhombic structure with space group Pbcn (60). A microflowers-like morphology with irregular hexagonal nanorods was observed using field emission scanning electron microscopy for the Yb
3+(2 mol%)/Er
3+(2 mol%):LWO nanophosphor. The shape and size of the nanophosphor and the elements along with their ionic states in the material were confirmed by TEM and XPS studies, respectively. A green upconversion emission was observed in the Er
3+: LWO nanophosphors under 980 nm laser excitation. A significant improvement in upconversion emission has been observed in the Er
3+: LWO nanophosphors by increasing the Er
3+ ion concentration. A decrease in the upconversion emission occurred due to concentration quenching when the doping concentration of Er
3+ ions was greater than 2 mol%. An optimized Er
3+(2 mol%): LWO nanophosphor exhibited a strong near infrared emission at 1.53 μm by 980 nm excitation. The green upconversion emission of Er
3+(2 mol%): LWO was remarkably enhanced by co-doping with Yb
3+ ions under 980 nm excitation because of energy transfer from Yb
3+ to Er
3+. The naked eye observed this upconversion emission when co-doping with 2 mol% Yb
3+. In order to obtain the high upconversion green emission, the optimized sensitizer concentration of Yb
3+ ions was found to be 2 mol%. The upconversion emission trends were studied as a function of stimulating laser power for an optimized sample. Moreover, the NIR emission intensity has also been enhanced by co-doping with Yb
3+ ions due to energy transfer from Yb
3+ to Er
3+. The energy transfer dynamics were systematically elucidated by energy level scheme. Colorimetric coordinates were determined for Er
3+ and Yb
3+/Er
3+: LWO nanophosphors. The energy transfer mechanism was well explained and substantiated by several fluorescence dynamics of upconversion emission spectra and CIE coordinates. The results demonstrated that the co-doped Yb
3+(2 mol%)/Er
3+(2 mol%): LWO nanophosphor material is found to be a suitable candidate for the novel upconversion photonic devices.
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