Multicolor emission and energy transfer dynamics in thermally stable Ca2Ga2SiO7:Tb3+/Eu3+ for warm w-LEDs application

Abstract

Tb3+/Eu3+ co-doped CGS phosphor was prepared successfully through solid-state reaction technique and their structural, and emission properties were inspected in depth. X-ray diffraction (XRD) represented single-phase tetrahedral structure of Ca2Ga2SiO7 having P4¯21m space group. The emission profile for Tb3+/Eu3+ co-doped CGS phosphor exhibited peaks in the different spectral regions (blue, green, orange, and red region) under 374 nm excitation. The energy transfer from Tb3+ to Eu3+ was ascribed to dipolar- dipolar interaction as confirmed by Dexter and Reisfeld theory with 49.5% ET efficiency. The emission color of the CGS phosphor can be modulated over a vast spectral region passing via white light region by appropriately regulating Eu3+ concentration. The obtained CIE chromaticity coordinates were (0.445, 0.416) with CCT value of 2966 K, indicating warm white light emission. The emission intensity for Tb3+/Eu3+ co-doped CGS phosphor at 423 K was 85.26% of that at 298 K, indicating strong thermal stability and potential applicability for w-LEDs application.