Crystal structure, photoluminescence and electroluminescence of (Ba,Eu)Si₂S₅

Abstract

Abstract Structural and optical properties of Ba 1− x Eu x Si 2 S 5 are investigated for 0 ⩽ x ⩽ 1. A monoclinic structure similar to SrSi 2 S 5 is maintained for the whole range of x . With the increase in x , continuous and isotropic decrease of lattice constants appears because of the replacement of Ba 2+ by smaller Eu 2+ . Raman and infrared absorption spectra show the existence of anions in BaSi 2 S 5 . Green photoluminescence (PL) originating from the 4f 6 5d–4f 7 transition of Eu 2+ is obtained. The maximum PL efficiency of 52% is found for x = 0.01. Wavelength variation of the PL peak between 500 and 524 nm for 0.01 ⩽ x ⩽ 0.9 can be understood by the presence of two Eu 2+ sites having different decay times in Ba x Eu 1− x Si 2 S 5 . Green PL and electroluminescence are obtained from (Ba,Eu)Si 2 S 5 fabricated on silicon substrate.