中文摘要：

采用水热法成功制备了Er~（3＋）/Yb~（3＋）双掺杂的NaGd（WO_4）_2纳米粉体,研究了不同络合剂、水热温度对样品形貌和结构的影响。测量了不同Er~（3＋）掺杂浓度样品的可见上转换和近红外发射光谱。结果表明：在980nm LD激发下,可观测到样品强烈的绿色上转换发光,对应Er~（3＋）的~2H_（11/2）→~4I_（15/2）（530nm）和~4S_（3/2）→~4I_（15/2）（552nm）跃迁,以及较弱的红色上转换和近红外发光,分别对应Er~（3＋）的~4F_（9/2）→4I15/2（656nm）和~4I_（13/2）→~4I_（15/2）（1 532nm）跃迁。且随着Er~（3＋）掺杂浓度的增加,样品的上转换红绿光和1.54μm附近的近红外光均呈现出先增大后减小的趋势。样品的激发和发射光谱显示,在378nm处的激发峰最强,对应Er~（3＋）的~4I_（15/2）→~4 G_（11/2）能级跃迁,最强发射峰位于552nm。根据泵浦功率与发光强度的关系可以得出,红光和绿光的发射主要为双光子吸收过程,但红光还包含了一定的单光子吸收成分。

英文摘要：

The Er3＋/Yb3＋ co-doped NaGd（WO4）2 powder were synthesized by the hydrothermal method. The effects of different complexing agents and hydrothermal temperature on morphology and structure of the samples were studied. The visible and near infrared emission spectra of the co-doped NaGd（WO4）2 powders with various Er3＋ ion concentrations were measured. The spectroscopic results show intense green emission bands, weak red emission and near infrared emission bands for the co-doped samples located at 530 nm, 552 nm, 656 nm and 1 532 nm under 980 nm LD excitation, which correspond to the 2H11/2/4S3/2→4I15/2,4F9/2→4I15/2 and 4I13/2→4I15/2 level transition of Er3＋, respectively. With the increase of Er3＋ concentration, the intensities of the upconversion and near infrared emission show a trend of increasing first and then decreasing. The most intense excitation and emission peaks are centered at 378 nm and 552 nm. According to the relationship between exciting power and luminous intensity, the red light and green light all belong to two-photon absorption processes, but the red light also contains a certain single photon absorption component.