Bright red emission from doubly doped YAG:Pr/Sm nanophosphor and color modulation

Abstract

Herein, we report the detailed structural and spectroscopic analysis of singly and doubly doped Pr3+and Sm3+ions in yttrium aluminium garnet (Y3Al5O12, YAG) host. The formation of YAG nanophosphor is confirmed by XRD patterns and TEM images revealing crystalline size in the range of 40–50 nm. The absorption peaks of the doubly doped sample are the conflation of the absorption due to both the Pr3+ and Sm3+ ions. The laser excitations by 405 and 450 nm yield sharp and intense emissions in the orange-red region due to the combinatorial emission of both the doped species. Results were estimated from the powder sample as well as homo and hetro-layered structures. The emission intensity was found to improve with the number of layers. The intensity of characteristic emission peaks of Sm3+ ions was found to reduce in presence of Pr3+ ions. XPS analysis reveals a change in valance state of Pr3+ to Pr4+ and Sm3+ to Sm2+ ion, which is reported to be responsible for the emission intensity reduction. The dual-beam excitation of Pr and Sm doped layer yield bright emission of both the species although the [email protected].1Pr layers yields a combinatorial emission with modified intensity. The time-resolved emission spectroscopy indicates the weak interaction between the doped species. Moreover, the codoped nanophosphors demonstrate modified color perception in comparison to the singly doped nanophosphor, as revealed by CIE coordinates calculation under different excitations.