Efficient host excitation in thiosilicate phosphors of lanthanide(III)-doped Y4(SiS4)3. (3rd February 2016)

• Record Type: Journal Article
• Authors: Nanai, Yasushi; Suzuki, Yousuke; Okuno, Tsuyoshi
• Is Part Of: Journal of physics. Volume 49:Number 10(2016)
• Publication Date: 2016-02-03
• Subjects: lanthanide -- luminescence -- phosphor -- sulfide -- thiosilicate; Physics -- Periodicals; 530
• DOI: 10.1088/0022-3727/49/10/105103
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: Lanthanide (Ln)-doped yttrium thiosilicate (Y1− x Ln x )4 (SiS4 )3 is synthesized, and its optical properties are studied. In (Y1− x Tb x )4 (SiS4 )3, the green photoluminescence band corresponding to the intra 4f transition of 5 D4 → 7 F5 appears at 545 nm and becomes the maximum for x = 0.2 in the range x = 0.01 to 1. The internal quantum efficiency is higher (11% for x = 0.01) for the thiosilicate host excitation (360 nm) than for the direct excitation (1.6%) of the intra 4f transition of 5 D4 ← 7 F6 (489 nm). A time-resolved photoluminescence study shows that the luminescence of defect states of thiosilicate hosts decays faster (typically 10–30 ns) for higher Tb 3+ concentration x . In addition, the rise time of Tb 3+ photoluminescence is shorter (10–40 ns) for greater x . Energy transfer from the thiosilicate host to Tb 3+ is discussed using these results. For all of (Y1− x Ln x )4 (SiS4 )3 ( x = 0.01, Ln = Pr, Nd, Dy, Er or Tm), the internal quantum efficiency is higher for the host excitation (11–21%) than for the direct excitation of intra 4f transitions (1.1–12%). A photoluminescence excitation study reveals broad host absorption in 300–400 nm for Ln luminescence. These results show the promising characteristics of the host absorption of (Y1− x Ln x )4 (SiS4 )3 phosphors and their optical properties.