Red photoluminescence due to energy transfer from Eu2+ to Cr3+ in Sr3Al10SiO20–SrAl12O19 mixed phases

Abstract

Sr3Al10SiO20–SrAl12O19, doped with Eu2+, Cr3+ and (Eu2+ + Cr3+) is prepared by solid-state reaction and energy transfer from Eu2+ to Cr3+ in the phase of Sr3Al10SiO20 is the focus of investigation. The spectrum of Sr3Al10SiO20–SrAl12O19 : Eu2+ shows f–d emission bands at 460 and 400 nm. Cr3+ doped Sr3Al10SiO20–SrAl12O19 yields emission lines at 688 and 696 nm and a broad emission band between 650 and 750 nm. The photoluminescence study and fluorescence lifetime measurements demonstrate efficient energy transfer from Eu2+ to Cr3+ in Sr3Al10SiO20 : Eu2+, Cr3+. The emission lines peak at 688 nm and 696 nm, which, respectively, originate from 2E–4A2 transitions in the phases of SrAl12O19 and Sr3Al10SiO20. The broad emission band of Cr3+ between 650 and 750 nm in the phase of Sr3Al10SiO20 is considered to be the 4T2–4A2 transition by calculating the strength of the octahedral crystal field Dq, the Racah parameters B and C as well as by constructing the Tanabe–Sugano diagram.