中文摘要：

采用溶胶-水热法制备了Yb^3＋-Ho^3＋-F^-共掺杂的TiO2（简写为UC-F-TiO2）纳米粉末。通过XRD,TEM,拉曼光谱,XPS和发光光谱,研究了Yb^3＋掺杂浓度对UC-F-TiO2纳米粉末的结构、形貌和上转换发光性能的影响规律。结果表明：UC-F-TiO2纳米粉末颗粒的大小约20 nm,由金红石和锐钛矿两种结构混合组成,且随着Yb^3＋掺杂浓度的增加,金红石结构的TiO2所占比例增加;在980 nm激光激发下,UC-F-TiO2发射出中心在543 nm、647 nm和751 nm处的三个发光带。研究了基于UC-F-TiO2和纯TiO2纳米多孔薄膜光阳极的染料敏化电池的光伏性能。结果表明：与纯TiO2制备的电池相比,将UC-F-TiO2应用于染料敏化电池,电池的光电转换效率提高了29.7%。

英文摘要：

The up-conversion Ho^3 ＋ -Yb^3 ＋ -F^- doped TiO2 （UC-F-TiO2） nanocrystals were synthesized by sol- hydrothermal method. The effect of Yb^3 ＋ concentrations on structure, morphology and upconversion luminescence properties of UC-F-TiO2 were studied by XRD, Raman spectroscopy, TEM, XPS and PL. The results show that the Ho^3 ＋ -Yb^3＋-F^- co-doped TiO2 nanocrystals are mixtures of anatase and rutile phases. The ratio of rutile/ anatase decreases as the Yb3＋ concentration increasing. The average size of UC-F-TiO2 nanocrystals is ？20 nm. Under the excitation of 980 nm NIR light, the UC-F-TiO2 nanocrystals emit strong up-conversion fluorescence with three emission bands at 543 nm, 647 nm and 751 nm. The photovoltaic performance of dye-sensitized solar cells based on UC-F-TiO2 and pure TiO2 nanoporous thin film photoanodes was studied. Compared with the pure TiO2 DSSCs, DSSCs with UC-F-TiO2 have higher IPCE and higher conversion efficiencies.