Optical, crystallographic and Judd–Ofelt analysis of europium doped Sr₆Y₂Al₄O₁₅ nanocrystals for NUV-WLED fabrication

Abstract

A very convenient and energy-saving route named Solution-Combustion Synthesis had been adopted to prepare a sequence of Sr₆Y₂Al₄O₁₅:Eu³⁺(1.0–5.0 mol%) nanophosphorshaving an excellent luminescence which is very requisite in the solid-state illumination sector. The monoclinic phase and the crystallinity of the prepared samples were confirmed by Powder X-Ray Diffraction and the Rietveld refinement technique. Non-uniformity and somewhat agglomeration of particles having a size between 32 nm and 62 nm, were observed during morphological probes via Scanning and Transmission Electron Microscopies. The red-light emission was due to electronic transition from ⁵D₀ → ⁷F₂ states which is purely electric-dipole allowed transition. Dexter’s approach as well as Inokuti-Hirayama model,were cast-off to look into photoluminescent properties. Both these models confirmed the multipolar interactions as the main cause for concentration quenching after 3.0 mol% of Europium(III) content. Various other radiative properties such as decay-time, quantum efficiency, non-radiative relaxation rates were also determined. Red light parameters like Color Coordinate Temperature and Commission International de I’Eclairage color coordinates were also evaluated which confirmed the potential candidature of the prepared nanophosphors for the most recent version of wLEDs, lasers, sensors, advanced solar cells, etc.