Mechanisms and absolute quantum yield of upconversion luminescence of fluoride phosphors

• 来源期刊: 中国光学快报（英文版）
• 年，卷（期）: 2018,（9）
• 页码范围: 60-64
• 页数: 5页
• 语种: 英文
• DOI: 10.3788/COL201816.091901

摘要

Mechanisms of upconversion luminescence (UCL) of SrF2∶Er phosphors corresponding to the 4G11/2 →4I15/2,2H9/2 →4I15/2,4F5/2→4I15/2,4F7/2 →4I15/2,2H11/2 →4I15/2,4S3/2 →4I15/2,4F9/2 →4I15/2,and 4I9/2→4I15/2 transitions upon excitation of the 4I11/2 level of Er3+ ions were investigated.Energy transfer upconversion processes are responsible for the populating of the 2H9/2,2H11/2,4S3/2,and 4F9/2 levels.Cooperative process is the dominant mechanism of luminescence from 4S3/2 and 4F9/2 levels for SrF2∶Er with high concentrations of Er3+ ions.The UCL from 4G11/2 and 4F5/2 is explained by excited-state absorption.Cross-relaxation processes take part in the population of 4F9/2 and 4I9/2 levels.For quantifying material performance,the Er3+-concentration dependence of UCL and the absolute quantum yields of SrF2∶Er were studied.The most intensive visible luminescence was obtained for SrF2∶Er (14.2％) with 0.28％ maximum quantum yield.