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利用水相合成的方法制备了巯基包覆的具有较高荧光量子产率的CdSe和CdSe/CdS纳米晶 .水相合成方法的优点是原料低廉、安全可靠和重复性高 ,缺点是纳米晶的尺寸分布较宽 ,发光效率不是很高 .采用X—射线粉末衍射、吸收和荧光等光谱手段对纳米晶的平均尺度、粒径分布、晶体结构及发光特性进行了表征。在 77K到 3 0 0K的温度范围内 ,随着温度降低 ,CdSe纳米晶的发光峰逐渐蓝移 ,而CdSe/Cds纳米晶发光峰位基本不随温度变化而变化 .此外 ,在 3 2 5nm激光辐照下 ,CdSe/CdS纳米晶的荧光寿命比CdSe纳米晶延长了 6倍左右 ,稳定性大幅度提高 .以上结果表明 ,核壳结构的CdSe/CdS纳米晶具有较高的发光效率和良好的稳定性 ,具有广阔的应用前景 .
The mercapto-coated CdSe and CdSe / CdS nanocrystals with high fluorescence quantum yield were prepared by aqueous phase synthesis.The advantages of the aqueous phase synthesis method are low cost, high safety, high reproducibility, and the disadvantage of nanocrystalline The size distribution is wide and the luminous efficiency is not very high.The average size, size distribution, crystal structure and luminescence properties of nanocrystals were characterized by X-ray powder diffraction, absorption and fluorescence spectroscopy. In the temperature range of 77K to 3000K, the luminescence peak of CdSe nanocrystals gradually blue-shifted with the decrease of temperature, but the peak of CdSe / Cds nanocrystals did not change with the temperature change.In addition, According to the above results, the fluorescence lifetime of CdSe / CdS nanocrystals is about six times longer than that of CdSe nanocrystals, and the stability is greatly improved. The results show that CdSe / CdS nanocrystals with core-shell structure have higher luminescent efficiency and good stability Sex, has broad application prospects.