根据荧光粉的发光特性,对荧光粉外量子效率测试系统中的光路进行改进.当测试参比样品和待测样品的反射光谱时,通过在光谱仪的狭缝1和传输光纤1之间插入中性衰减片,对激发光源的发光强度进行有效调节;当测试发射光谱时,则取下该中性衰减片,使样品的荧光发射强度接近于衰减后的激发光源强度.对同一个样品进行10次测量之后,发现其测量结果的标准差从3.66降低到0.47,可有效提高测量精度.同时,研究荧光粉质量浓度对其外量子效率的影响,结果表明:荧光粉浓度越低,外量子效率越高,其最佳测量浓度约为50%,此时外量子效率接近于真实值.%The beam path of external quantum efficiency (EQE) testing system was improved according to luminescent properties of phosphors. When the reflectance spectra of reference and tested samples were being tested, a neutral optical filter was inserted into beam path between slit 1 and transmission fiber 1 in spectrometer. As a result, the reflective intensity of excitation light was regulated effectively. When the photoluminescence(PL) spectra were being tested, the previous neutral optical filter was taken out. So the PL intensity of tested samples were close to that of reduced excitation light. The standard deviation of EQE values was realized by testing one sample for many times. The value of standard deviation was reduced from 3.66 to 0.47. It indicated that the accuracy of measurement was greatly enhanced. Moreover, the dependence of EQE on phosphor concentration has also been studied. Results show that the lower concentration can cause higher EQE value. The optimized concentration is about 50%. Under this concentration, the achieved EQE value is close to real value.
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