摘要/Abstract

报道了一种简易、快速调节量子点荧光波长的方法.以GSH为配体水热法合成了发射波长为540 nm左右的绿色荧光CdTe量子点，通过（NH₄）₂MoS₄在加热和常温条件下引导CdTe量子点进行自组装.加热条件下，15 min内可以使发射波长迅速的红移100 nm以上.常温条件下，在48 h内可以缓慢的引导CdTe量子点进行自组装，发射波长缓慢红移70 nm以上.利用对比实验验证了（NH₄）₂MoS₄中的MoS₄^2-对引导CdTe量子点自组装具有特异性，并且构建了一个合理的自组装体的结构单元模型.在细胞成像领域，该自组装体具有潜在的应用前景.
关键词: CdTe量子点, (NH₄)₂MoS₄, 自组装, 模型, 细胞成像
Conventionally, red shift of QD photoluminescence (PL) could be achieved by growing QDs to larger sizes using hydrothermal method, which is usually a very slow process. We synthesized green fluorescent CdTe quantum dots with GSH as the ligand and proved the successful synthesis of (NH₄)₂MoS₄ by UV-Vis, X-Ray Diffraction, Raman spectroscopy. In the process of research, we found that (NH₄)₂MoS₄ can change the wavelength of CdTe quantum dots under the condition of heating or at room temperature. Redshift of emission wavelength can change with the different ratio between (NH₄)₂MoS₄and CdTe QDs. In this study, we report a rapid and convenient method to achieve red-shift of CdTe QD PL via (NH₄)₂MoS₄-guided QD self-assembly. We show that the emission wavelength of CdTe QDs underwent a red-shift of more than 100 nm for 15 min at 100℃ in the presence of (NH₄)₂MoS₄. At the same time, we conduct a experiment, which have no red-shift in the absence of (NH₄)₂MoS₄ for 15 min at 100℃. This illustrates that the (NH₄)₂MoS₄ plays an important role in CdTe QDs self-assembly. The red-shift of QD PL was also observed at room temperature but relatively slower. The formation of QD assembly was confirmed by gel electrophoresis, transmission electron microscopy, and X-ray photoelectron spectroscopy. The result of gel electrophoresis and transmission electron microscopy directly shows the self-assembly morphology of CdTe QDs and the change of size and shape. Self-assembly entity was proved to contain Mo and Cd by the X-ray photoelectron spectroscopy, which confirmed the connection between (NH₄)₂MoS₄and CdTe QDs. A control experiment was conducted by replacing (NH₄)₂MoS₄with Na₂S for QD assembly, in that case no apparent change of emission wavelength was observed. These results reveal that MoS₄^2- within (NH₄)₂MoS₄ is crucial for self-assembly of CdTe QDs. Accordingly, we propose a reasonable model of (NH₄)₂MoS₄-guided CdTe QD self-assembly. In this model, we consider the connection between a (NH₄)₂MoS₄ and two CdTe QDs in ideal condition. With the increasing ratio of (NH₄)₂MoS₄, much more connection between (NH₄)₂MoS₄ and CdTe will be obtained. Assembling entity morphology changed with different cross-linking way. The resulting QD assembly was further applied to cell imaging experiments, demonstrating their potentials in this field.
Key words: CdTe QDs, (NH₄)₂MoS₄, self-assembly, model, cell imaging


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