Er3+/Yb3+ codoped phosphor Ba3Y4O9 with intense red upconversion emission and optical temperature sensing behavior. Issue 13 (20th March 2018)

• Record Type: Journal Article
• Authors: Wu, Hao; Hao, Zhendong; Zhang, Liangliang; Zhang, Xia; Xiao, Yu; Pan, Guo-Hui; Wu, Huajun; Luo, Yongshi; Zhang, Ligong; Zhang, Jiahua
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 13(2018)
• Page Start: 3459
• Page End: 3467
• Publication Date: 2018-03-20
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c7tc05796b
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : Bright red upconversion phosphor Ba3 Y4 O9 :Er 3+ /Yb 3+ and dual-color complementary optical thermometry to maintain relatively high sensitivities over a wide temperature scope. Abstract : The Ba3 Y4 O9 host matrix with a low cutoff phonon energy of 585 cm −1 is first applied to upconversion (UC) luminescence (UCL) by codoping Er 3+ /Yb 3+ . The new phosphor shows an intense red UC emission which is 6.8-fold and 5.9-fold stronger than that of Y2 O3 and β-NaYF4, respectively, under 980 nm GaAs laser diode (LD) excitation at a low density. A broad absorption band centered at 976 nm is observed, meaning a high adaptability to the GaAs LD required in actual applications. The optical thermometry behaviors based on the temperature dependent fluorescence intensity ratios of thermally coupled green UC bands 2 H11/2 → 4 I15/2 and 4 S3/2 → 4 I15/2 as well as the thermally coupled red UC emission bands originating from the Stark sublevels of 4 F9/2 manifold have been explored. The results show that green emissions are suitable for temperatures above 350 K with the maximum sensitivity of 0.00248 K −1 at 563 K and the red emissions are appropriate for temperatures below 350 K with the maximum sensitivity of 0.00371 K −1 at 143 K in our experimental range, indicating their complementary temperature sensing ranges. Moreover, a new method is proposed for evaluating the radiative lifetime of the Er 3+ 4 F9/2 state based on the analysis of photoluminescence (PL) spectra and fluorescence decay curves. The radiative lifetime of 879 μs for the red emitting level in Ba3 Y4 O9 is achieved. Thereby, the emission efficiency of 4 F9/2 in the new UCP is a little higher than that in Y2 O3 . Our results imply that Ba3 Y4 O9 :Er 3+ /Yb 3+ is a promising UCP, which could be applied to wide scope optical thermometry using a dual-color scheme.