Effect of OH on upconversion luminescence of Er-doped oxyhalide tellurite glasses

The Raman spectra, infrared spectra and upconversion luminescence spectra were studied, and the effect mechanism of OH⁻ groups on the upconversion luminescence of Er³⁺-doped oxyhalide tellurite glasses was analyzed. The results show that the phonon energy of lead chloride tellurite (PCT) glass was lower than that of lead fluoride tellurite (PFT) glass, but upconversion luminescence intensity of Er³⁺-doped PFT glass was higher than that of Er³⁺-doped PCT glass. The analysis considers that it was attributed mainly to the effect of OH⁻ groups. The lower the absorption coefficient of the OH⁻ groups, the higher the fluorescence lifetime of Er³⁺, and as a result the higher upconversion luminescence intensity of Er³⁺. In this work, the effect of OH⁻ groups on the upconversion luminescence of Er³⁺ was bigger than that of the phonon energy.     

电子俘获型薄膜材料的结构与光学性能

采用电子束沉积技术成功制务了以碱土金属硫化物为基质材料，稀土元素离子作为激活中心的输出红光的红外上转换及光存储薄膜材料ＣａＳ：Ｅｕ，Ｓｍ物相结构测试表明，基片温度和后退火晶化处理对薄膜的晶态有很大影响，在本实验的制备条件下，（２００）面的衍射蜂最强；加硫共蒸或通入少量Ｈ２Ｓ有助于改善ＣａＳ薄膜的化学计量比，光谱测试表明，薄膜材料的光学性能与粉末材料基本相同。     

The study of two-color excitation upconversion of Pr(0.5)Yb(3):ZBLAN

The excited state absorption upconversion of Pr(0.5)Yb(3):ZBLAN glass material, under two-color excitation of the 960 nm semiconductor laser and the Xe lamp light simultaneously, is reported in this article. It was found that the upconversion emission spectra of 480.1, 519.0, 601.9 and 631.8 nm coincide with the common emission spectra. Meanwhile, the upconversion-excitation spectrum has three obvious peaks under two-color excitation, and they respectively correspond to the 856.0 nm upconversion excitation transition [¹G₄(Pr³⁺)→¹I₆(Pr³⁺) and ¹G₄(Pr³⁺)→³P₁(Pr³⁺)], the 789.0 nm upconversion excitation transition ¹G₄(Pr³⁺)→³P₂(Pr³⁺), and the 803.7 nm upconversion excitation transition ³H₆(Pr³⁺)→¹D₂(Pr³⁺). The upconversion excitation transition ¹G₄(Pr³⁺)→¹I₆(Pr³⁺) is strong because its oscillator strength f = 23.040×10⁻⁶ is large, which results in a large peak appearing in the upconversion excitation spectrum. That is just the new interesting two-color excitation upconversion luminescence phenomenon of Pr(0.5)Yb(3):ZBLAN induced by one laser and one continuous normal light simultaneously.     

兼具三线态-三线态湮灭上转换与单光子吸收上转换特性的氮杂蒽衍生物发光性能研究

弱光上转换是将低能量光子转换为高能量光子的过程,在三维荧光显微成像、太阳能电池、光催化等领域具有广泛的潜在应用,因而成为有机荧光材料领域的热点课题。目前基于三线态-三线态湮灭机制有机弱光上转换材料（TTA-UC）的研究已较为深入,有关发光机理及应用研究均有较多报道;然而针对另一种有机弱光上转换机理——基于单光子热带吸收的弱光上转换（OPA-UC）的研究目前还较为少见。氮杂蒽衍生物由于具有良好的结构刚性和平面性,高的荧光量子产率,是研究TTA-UC和OPA-UC两种有机上转换发光的理想模型分子结构。通过研究比较三种氮杂蒽衍生物：酚藏花红（PSF）、藏红T（SFT）、亚甲基紫（MTV）各自TTA-UC和OPA-UC的发光性能差异,分析探讨了分子结构对OPA-UC发光性能及TTA-UC敏化效率的构效关系。实验发现酚藏花红和藏红T由于具有较高的荧光量子产率,同时辐射衰减常数较大,其主要衰减过程为辐射衰减;而亚甲基紫具有较高的分子内电荷转移能力(ICT),因而非辐射衰减部分更多。研究三种分子的TTA-UC性能,发现亚甲基紫的三线态能级过低无法进行三线态-三线态能量转移过程,而藏红T由于拥有更高的三线态寿命而具有更高的上转换发光效率(9.69%),是酚藏花红体系(3.16%)的3倍。进一步研究酚藏花红和亚甲基紫的OPA-UC性能差异,发现相同浓度条件(10-3 mol·L-1)下亚甲基紫(0.12%)的OPA-UC发光效率相较于酚藏花红(0.059%)更高,且随着浓度的升高,亚甲基紫的OPA-UC发光增强效应更大。进一步研究表明,在TTA-UC发光过程中,敏化剂的敏化效率主要受分子三线态寿命以及系间窜跃能力影响,寿命越长,系间窜跃能力越强,敏化效率越高;而在OPA-UC发光过程中,湮灭剂分子的发光学率主要受ICT影响,ICT能力越大,分子发光效率越高。使用氮杂蒽分子廉价易得,对未来高性能TTA-UC和OPA-UC发光分子的设计具有一定的实际意义。     

OH-对Er掺杂的亚碲酸盐氟氧化物玻璃上转换发光的影响

Er掺杂的亚碲酸盐玻璃具有很好的上转换性质,加入氟化物在干燥的气氛下可以制备低OH^-根含量的氟氧化物玻璃,同样组分在湿润的气氛下,仍有较高的OH^-根含量.通过傅里叶红外吸收光谱、荧光衰减曲线及上转换光谱研究了在干燥和湿润气氛下,亚碲酸盐氟氧化物玻璃的OH^-含量,以及对上转换发光的影响.在干燥的气氛下制备的亚碲酸盐玻璃的OH^-浓度为0.017×10²⁰cm^-3是湿润的气氛下制备玻璃中的1/15,其543nm绿光上转换效率增加了2.4倍.     

掺Tm3+石英光纤中频率上转换产生可见光的实验研究

报道了实验研究连续锁模1053nmNd:YLF激光泵浦的掺Tm³⁺石英光纤中可见光区的频率上转换过程.测量了可见荧光光谱,并用Tm离子的分步三光子吸收过程解释了可见光频率上转换现象.     

Synthesis and Analysis of Tm3+ Doped YF3 Upconversion Luminescent Nano-materials

<正>Upconversion(UC)phosphor Tm~(3+)doped YF_3 nano-crystals were prepared by hydrothermal method under different conditions and characterized by Field Transmission electron microscopy(TEM),Scanning electron microscopy(SEM)and X-ray diffraction(XRD).Their UC luminescence properties were studied by fluorescence spectrophotometer with 980 nm diode laser excitation,and impact of different grain sizes and morphology on the UC luminescence intensity was discussed.The fluorescence decay lifetime was calculated by Multi-exponential function fitting method.Results show that UC emission intensity was enhanced with the reduction of grain size,and the decay lifetime is 0.60 us.     

NaYF4:Yb3+/Er3+单颗粒微米棒偏振上转换发光及其取向示踪※

稀土掺杂微/纳材料的偏振上转换发光在单颗粒示踪和生物医学等领域具有广泛的应用前景. 稀土离子的偏振上转换发光主要取决于其局域态的电子结构和激发态动力学. 利用单颗粒偏振上转换光学测试平台对β-NaYF₄:Yb³⁺/ Er³⁺微米棒的偏振上转换发光进行了系统研究. 随发射偏振角的变化, 单个微米棒的上转换发光强度发生周期性改变, 且来自Er³⁺同一光谱支项的不同晶体场子能级跃迁的偏振方向不同. 与光谱支项整体的上转换发光相比, 其晶体场子能级上转换发光表现出更大的发射偏振度. 利用Er³⁺高度偏振的晶体场跃迁谱线, 实现了对单个微米棒空间取向的动态分析, 揭示了NaYF₄:Yb³⁺/Er³⁺微米棒作为偏振各向异性的上转换荧光探针在单颗粒取向示踪方面的潜在应用.     

基于cypate光裂解的新型近红外光响应稀土上转换纳米载药系统※

光响应药物释放体系具有非侵入性、远程可控且时空分辨率高等特点, 在杀菌、抗癌等生物医学领域具有重要应用价值. 但目前近红外光响应的光裂解药物递送体系报道较少且光响应效率还有待提高. 本工作将稀土纳米颗粒包覆介孔二氧化硅, 逐步偶联近红外染料cypate、金刚烷胺和β-环糊精来封堵孔口, 利用cypate的自敏光氧化断键作为光响应开关, 成功构建了一种新型近红外光响应稀土上转换纳米载药系统. 该纳米载药系统负载抗生素氧氟沙星表现出极低的药物流失率和较高的808 nm光照释放效率, 并且通过控制光照时间可以满足不同的给药量需求. 体外抗菌实验结果进一步验证了该纳米载药系统的光响应药物释放性能. 此外, 该纳米载药系统在980 nm激光激发下的上转换发光较强且不影响药物释放, 可以实现纳米载药系统的药物定位和生物成像功能. 本研究为发展高效光响应载药体系提供了新的思路.