采用溶胶-凝胶方法制备了到目前为止已见报道的效率最高, 化学性能稳定的上转换发光材料BaGd2ZnO5∶4％Yb3+, 1％Er3+纳米晶体。XRD数据表明样品为纯相, 属于正交晶体, 空间群为Pbnm, SEM图片显示所制备的样品尺寸约为150 nm左右, 分布均匀。样品在971 nm半导体激光器激发下, 产生强烈的绿光发射, 肉眼可视, 上转换强度与泵浦能量关系n=1.22为双光子实现了上转换发射。它们来自Er3+ 2H11/2→4I15/2和4S3/2→4I15/2 的跃迁发射, Er3+主要的激发态吸收(ESA)过程是: 4I15/2→4I11/2→4F7/2→2H11/2,4S3/2, Yb3+吸收截面很大(104 cm-1)容易传递它的激发态能量到Er3+, 提升了Er3+ 2F7/2的布局粒子数和能态, 进而提升了光谱中各个峰的强度。由于Er3+的2H11/2和4S3/2能级间距较小, 电子在这两能级的布居符合玻尔兹曼分布是温度的函数, 因此可以通过监测这两个能级发射强度比例(FIR)来测量基质材料的温度。这种方法不干扰被测对象的温度场, 可消除测量精度的不确定性,具有较宽的温度测试范围及合理的温度分辨率, 使用的泵浦源简单、方便、低廉, 更具商用价值。样品的温度变化范围350～800 K时, 温度测量灵敏度最高可达0.003 1 K-1。同时, 它在较低的激发密度下就能产生较高上转换发射功率, 使其成为远距离非接触温度测量的理想材料。

By far, the most efficient up-conversion nanocrystals luminescence materials BaGd2ZnO5∶4%Yb3+,1%Er3+, with stable chemical performance, were prepared by using Sol-gel method. XRD pattern shows that the sample is pure phase, belongs to the orthogonal crystals, and space group is Pbnm;SEM micrograph shows that the prepared sample of the morphology sized around 150 nm is evenly distributed. Samples with 971 nm semiconductor laser excitation produce a strong green emission, visible to the naked eye, and up-conversion strength and pump energy relation n=1.22 is two-photon for the realization of the up-conversion emission. They originated from Er3+ ions 2H11/2→4I15/2 and 4S3/2→4I15/2 transition emission, Er3+ ions main excited state absorption (ESA) process is: 4I15/2→4I11/2→2F7/2→2H11/2, 4S3/2, Yb3+ was added because of its large absorption cross section (104 cm-1) so that it is easy to transfer excitation energy to the Er3+ ions which enhance the layout particles number and the energy state of the 2F7/2, thereby enhancing the intensity of the peaks of the spectrum. Fluorescence intensity ratio (FIR) technique based on the green up-conversion emission of the sample has been studied because the Er3+ ions 2H11/2 and 4S3/2 energy level spacing is small. The electrons at the two levels conform to the Boltzmann distribution which is a function of temperature, and thus the fluorescence intensity ratio of two levels can be used to measure the temperature of the substrate material. This method does not interfere with temperature field of the measured object, and can eliminate the uncertainty of the accuracy;the test has a wide temperature range and reasonable temperature resolution, the pump source used is simple, convenient and inexpensive, and has more commercial values. The temperature range of the samples is from 350 to 800 K, and the highest temperature measuring sensitivity can reach 0.003 1 K-1. At the same time, under low excitation density, it can produce higher conversion transmission power, making it become ideal material for distance non-contact temperature measurement.