Thermal enhancement of the 2H11/2 → 4I15/2 up-conversion luminescence of Er3+-doped K2Yb(PO4)(MoO4) phosphors. Issue 36 (9th August 2021)

• Record Type: Journal Article
• Authors: Cui, Hongqiang; Cao, Yongze; Zhang, Lei; Zhang, Yuhang; Ran, Siying; Cao, Long; Wang, Yichao; Wu, Danyang; Li, Xiangping; Zhang, Xizhen; Zhang, Luran; Chen, Baojiu
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 36(2021)
• Page Start: 12159
• Page End: 12167
• Publication Date: 2021-08-09
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d1tc02442f
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : K2 Yb(PO4 )(MoO4 ):Er 3+ has a thermal enhancement of 2 H11/2 → 4 I15/2 up-conversion luminescence and a high temperature sensitivity. Moreover, at high temperatures, its green intensity is comparable to commercial NaYF4 :Er 3+ /Yb 3+ . Abstract : Er 3+ with different concentrations doped K2 Yb(PO4 )(MoO4 ) phosphors were prepared by a solid-state reaction method, and the layered orthorhombic crystal structure of the samples was confirmed by X-ray diffraction (XRD). Under the excitation of a 980 nm laser, the up-conversion luminescence (UCL) emission spectra of K2 Yb1− x (PO4 )(MoO4 ): x Er 3+ ( x = 0.05, 0.1, 0.5, 1, 2, 4, 6, and 14 mol%) phosphors were obtained, and moreover, the critical quenching concentration of Er 3+ was found to be 1 mol%. Furthermore, the up-conversion (UC) optical temperature behaviors of the Er 3+ -doped K2 Yb(PO4 )(MoO4 ) phosphors were investigated. All phosphors showed a thermal enhancement of UCL corresponding to the 2 H11/2 → 4 I15/2 transition of Er 3+ because of structural distortion, eliminating the energy transfer of Yb 3+ to Er 3+ through Er 3+ single-doped isostructural K2 Bi(PO4 )(MoO4 ) with thermal enhancement UCL of the 2 H11/2 → 4 I15/2 transition. In addition, the variable temperature XRD results suggest that the K2 Yb(PO4 )(MoO4 ) host is a thermal expansion material, and the variable temperature confocal Raman spectra results confirm the thermal expansion and structure distortion of PO4 or MoO4 tetrahedra. With the increase in the sample temperature, the UCL emission intensity of the 2 H11/2 → 4 I15/2 transition of Er 3+ ions at 663 K of K2 Yb0.999 (PO4 )(MoO4 ):0.001Er 3+ is up to 5.6 times that of 303 K. Through the fluorescence intensity ratio (FIR) technique, the corresponding maximum absolute sensitivity ( S A ) was derived to be 0.00866 K −1 at 550 K. The results indicate that the K2 Yb(PO4 )(MoO4 ) phosphors with a low Er 3+ doping concentration can be applied at high temperatures as optical thermometers.