Optical interactions and white light emission in Eu:Y2O3/YAG:Ce nanophosphor

Abstract

Detailed structural and optical analysis of composite nanophosphor (Eu:Y2O3)/(Y3Al5O12:Ce) was presented and compared with Eu:Y2O3 and Y3Al5O12:Ce (YAG:Ce) nanophosphors. The nanophosphor was synthesized by adopting the combustion synthesis route subsequently co-precipitation method. The detail structural and spectroscopic characterizations were carried out using different techniques including XRD, TEM, SEM, FTIR, and PL. The XRD analysis indicates the formation of tiny crystals (12–24 nm) which was supported by SEM and TEM images. FTIR absorption spectra confirm the coordination between Eu:Y2O3 and YAG:Ce phosphors. The laser excitations by 405 nm and 450 nm stimulate sharp and intense red emission in Eu:Y2O3 and a broad asymmetric green–yellow emission in YAG:Ce nanophosphor. The Eu:Y2O3/YAG:Ce composite nanophosphor yields combinatorial emissions of Ce3+ and Eu3+ ions; though, the intensity was found to be modified due to the interaction between the ions doped in nanophosphors. The emission of Eu:Y2O3/YAG:Ce was extended in the red region (670 nm). Detailed emission properties were investigated on 342, 381, 405, 450, and 464 nm excitations, in addition to dual-beam excitations (405 nm + 450 nm). The energy transfer from Ce3+ → Eu3+ ions was established on the basis of emission intensity improvement in the Eu3+ ion at the cost of the emission intensity of Ce3+ ion and appearance of Eu3+ ion emission while exciting Ce3+ ion. The color perception of the nanophosphor was observed to be significantly modified at different excitation wavelengths, and laser power as reflected by CIE coordinates. The detail photophysics of the observed modification is well explained.