| 柠檬酸稳定的水溶性CdSe和CdSe/CdS量子点的荧光特性 |
| Photoluminescence Properties of Citrate-stabilized Water-soluble CdSe and CdSe/CdS Quantum Dots |
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| 摘要: 用柠檬酸(citrate)作为稳定剂合成了尺寸分布集中、荧光性质良好的水溶性CdSe量子点。通过调节合成温度可以调控CdSe量子点的尺寸及相应的最大荧光发射波长。当温度由20 ℃增加到95 ℃时，合成的CdSe量子点的平均尺寸由2.0 nm增加到3.2 nm，相应的荧光发射峰由500 nm红移到570 nm，展现出明显的量子尺寸效应。进一步制备了CdSe/CdS核壳量子点，其荧光量子产率比CdSe增加了5～10倍。系统地研究了S/Se物质的量的比对CdSe/CdS量子点荧光特性的影响，通过XPS证实了CdSe/CdS量子点中CdS壳层的存在。利用红外光谱和核磁共振波谱表征了柠檬酸分子中的羧基和羟基氧原子与CdSe量子点表面的Cd离子的配位作用，进而揭示了柠檬酸分子对水溶性CdSe量子点溶液的稳定作用。 |
| 关键词: CdSe CdSe/CdS 半导体量子点 柠檬酸三钠 |
| 基金项目: |
| Abstract: Narrow distributed and highly luminescent CdSe nanoparticles (NPs) were synthesized by using citrate as the stabilizer in aqueous system. The size distribution and corresponding emission maximum of CdSe NPs could be tuned accurately by controlling the synthesis temperature. As the synthesis temperature increased from 20 ℃ to 95 ℃, the diameter of the as-prepared CdSe NPs increased from 2.0 nm to 3.2 nm, and the corresponding emission maximum red-shifted from 500 nm to 570 nm. Hence, these as-prepared water-soluble CdSe NPs exhibit obvious quantum confinement effects. The core-shell CdSe/CdS NPs were prepared further whose luminescence intensities enhanced 5～10 times as compared with those of CdSe core NPs. The influence of the precursor molar ratio of S and Se on the photoluminescence properties of CdSe/CdS nanoparticle solutions was studied and the existence of CdS on CdSe/CdS NPs was confirmed by means of XPS. FTIR and 1H NMR were used to characterize the coordination of the oxygen atoms in citrate molecules with the Cd2+ ions on the surfaces of CdSe NPs. The results indicate the role of citrate molecules in improving the stability of water-soluble CdSe NPs. |
| Keywords: CdSe CdSe/CdS semiconductor quantum dots trisodium citrate |
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| 邓大伟,于俊生.柠檬酸稳定的水溶性CdSe和CdSe/CdS量子点的荧光特性[J].无机化学学报,2008,24(5):701-707. |
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