Energy Transfer Dynamics and Quantum Yield Derivation of the Tm3+ Concentration-Dependent, Three-Photon Near-Infrared Quantum Cutting in La2BaZnO5

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• 作者：Ting Yu ; Huihong Lin ; Dechao Yu ; Shi Ye ; Qinyuan Zhang
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：November 25, 2015
• 年：2015
• 卷：119
• 期：47
• 页码：26643-26651
• 全文大小：578K
• ISSN：1932-7455

文摘

Near-infrared (NIR) quantum cutting (QC) from the Tm³⁺: ¹G₄ state essentially occurs via a three-step cascade radiation (case 1) and two-step cross-relaxations (case 2) by varying the Tm³⁺ content (x) from 0.0005 to 0.05 in La_2鈥?i>xTm_xBaZnO₅. In case 1, with the Tm³⁺ content x < 0.005, the energy of the ¹G₄ excited state is down-converted to three NIR photons emitted at approximately 1200, 1480, and 1800 nm, with ³H₄ and ³F₄ acting as intermediate levels, while in case 2, with the Tm³⁺ content x 鈮?0.005, the energy will be triply cut into approximately 1800 nm photon emissions. The three-photon NIR QC phenomena are investigated in terms of the static and dynamic photoluminescence. Based on the dependence of cross-relaxation and concentration quenching on Tm³⁺ density, a rate-equation model was built to describe the energy transfer (ET) dynamics of Tm³⁺. The calculation of internal quantum yield (QY) was developed by considering nonradiative processes, and the maximum QY for photon emission at 1800 nm was 198% in La_1.99Tm_0.01BaZnO₅. These phenomena provide insight into the triple cutting mechanisms of Tm³⁺-doped materials, thereby improving the potential applications of this quantum tripling in Ge photovoltaic devices (band gap approximately 0.67 eV), and laser devices.