A double perovskite structure Ca2InTaO6:Sm3+ orange-red phosphor with high thermal stability for high CRI w-LEDs and plant growth lighting

Abstract

A novel Sm3+-doped Ca2InTaO6 (CITO:Sm3+) phosphor was produced through a high-temperature solid-state reaction. The Rietveld refinement of the CITO:Sm3+ phosphors were carried out, and its successful synthesis was demonstrated. The phosphor is a member of the Pnma space group (No.62) and features a double perovskite structure. The excitation spectrum of CITO:5 mol%Sm3+ revealed a suitable excitation at 407 nm. The emission spectrum exhibited four distinct peaks. The most intense emission peak is at 601 nm, attributed to the 4G5/2-6H7/2 radiative transition of Sm3+ ions. The emission spectra at different doping concentrations indicated the optical doping concentration of 5 mol%. Dipole-dipole interactions are the reason for the concentration quenching. The internal and external quantum efficiency of CITO:5 mol%Sm3+ is 73.52 % and 38.73 %, respectively. In the range of 300–480 K, CITO:5 mol%Sm3+ phosphor demonstrated high thermal stability and had almost no thermal quenching phenomenon. The CITO:5 mol%Sm3+ phosphor has an activation energy (Ea) of 0.289 eV. The electroluminescence spectra of the fabricated orange-red light-emitting diode (LED) can match the absorption spectra of PR, PFR, chlorophyll b, phycocyanin, and allophycocyanin. The white LED (w-LED) prepared with this phosphor has Commission Internationale de l'Eclairage (CIE) chromaticity coordinates of (0.339, 0.331) and a correlated color temperature of 5184 K, as well as an excellent color rendering index (Ra = 94). These indicate the promising usage of CITO:Sm3+ in plant-growth and w-LED illumination.