La2O2SO4:RE/Yb new phosphors for near infrared to visible and near infrared upconversion luminescence (RE=Ho,Er, Tm) |
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| Authors: | Xuejiao Wang Zhipeng Hu Qi Zhu Ji‐Guang Li Xudong Sun |
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| Affiliation: | 1. College of New Energy, Bohai University, Jinzhou, Liaoning, China;2. Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki, Japan;3. Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang, Liaoning, China;4. Institute of Ceramics and Powder Metallurgy, School of Materials Science and Engineering, Northeastern University, Shenyang, Liaoning, China;5. Liaoning Engineering Laboratory of Special Optical Functional Crystals, School of Environment and Chemical Engineering, Dalian University, Dalian, Liaoning, China |
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| Abstract: | The 3 new upconversion (UC) phosphors of La2O2SO4:RE/Yb (RE=Ho, Er, and Tm, respectively) were derived via facile dehydration of their layered hydroxide precursors that were hydrothermally synthesized at 100°C. Rietveld XRD refinement found contracting cell dimension with decreasing RE3+ size, confirming the direct crystallization of solid solution. The Er3+ and Ho3+ activators both exhibited simultaneous green and red (dominant) emissions under 978‐nm near‐infrared (NIR) laser excitation (NIR‐Vis UC). Particularly, Tm3+ produced a Gaussian‐shaped pure NIR emission band at ~812 nm via its 3H4 → 3H6 transition (NIR‐NIR UC), which is highly desired for NIR biological application. Analysis of the excitation‐power dependent UC properties manifested a 3‐photon mechanism for the 3 phosphors, and the possible photon reactions leading to UC were illustrated. |
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| Keywords: | layered rare‐earth hydroxide oxysulfate upconversion luminescence |
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