Wang Xin, Li Xiangping, Shen Rensheng, Xu Sai, Cheng Lihong, Sun Jiashi, Zhang Jinsu, Chen Baojiu
College of Science, Dalian Maritime University, Dalian, Liaoning, 116026, PR China.
College of Science, Dalian Maritime University, Dalian, Liaoning, 116026, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2019 Jun 15;217:107-112. doi: 10.1016/j.saa.2019.03.080. Epub 2019 Mar 24.
Usually, the luminescence intensity and mechanism of rare-earth ions doped materials are dependent on both doping concentration and sample temperature. In this study, we attempt to explore the concentration effect on up-conversion (UC) luminescence and the dependence of luminescence temperature quenching on excitation wavelength in YNbO: Ho/Yb phosphors. The YNbO: Ho/Yb phosphors with various Ho and Yb concentrations were synthesized via a high-temperature solid-state reaction technique. Intense green UC emission peaked at 543 nm was observed, accompanying with weak red and near infrared (NIR) UC emissions centered at 659 and 745 nm. Based on the laser working current dependence of UC luminescence, two-photon processes were responsible for both the green and the red UC emissions under 980 nm excitation, which have no apparent dependence on both Ho and Yb concentrations. According to the Arrhenius model, crossover process was responsible for the temperature-dependent down-conversion (DC) luminescence quenching of Ho under 452 nm excitation. However, the temperature quenching processes of the green and the red UC luminescence cannot be well explained by Arrhenius model. It was found that the UC luminescence intensity decayed with increasing sample temperature, which was caused by both the crossover and temperature-dependent energy transfer processes.
通常，稀土离子掺杂材料的发光强度和机制既取决于掺杂浓度，也取决于样品温度。在本研究中，我们试图探究钇铌酸盐：钬/镱荧光粉中浓度对上转换（UC）发光的影响以及发光温度猝灭对激发波长的依赖性。通过高温固相反应技术合成了具有不同钬和镱浓度的钇铌酸盐：钬/镱荧光粉。观察到在543 nm处出现强烈的绿色UC发射峰，同时伴有以659和745 nm为中心的微弱红色和近红外（NIR）UC发射。基于UC发光对激光工作电流的依赖性，在980 nm激发下，双光子过程导致了绿色和红色UC发射，且这两种发射对钬和镱浓度均无明显依赖性。根据阿伦尼乌斯模型，在452 nm激发下，交叉过程导致了钬的温度依赖性下转换（DC）发光猝灭。然而，绿色和红色UC发光的温度猝灭过程无法用阿伦尼乌斯模型很好地解释。研究发现，UC发光强度随样品温度升高而衰减，这是由交叉过程和温度依赖性能量转移过程共同导致的。
