研究目的
Investigating the synthesis, characterization, and photoinduced electron-transfer energetics of CdTe/CdSe type-II core/shell quantum dots.
研究成果
The CdTe/CdSe type-II core/shell QDs were fabricated via the colloidal synthesis by continuous deposition of Cd and Se organometallic precursors onto CdTe core QDs. The PL peak of CdTe/CdSe type-II core/shell QDs could be adjusted from 698 nm (1.77 eV) to 780 nm (1.59 eV). The reorganization energies of the type-II QDs for the electron transfer depend on structure, shape, as well as the size of QDs. Marcus theory has been used to study the CT of CdTe/CdSe 1-5ML core/shell QDs and it was found that ET takes place in the Marcus inverted region (-?G°ET> λCT).
研究不足
The PL QYs of CdTe/CdSe QDs are lower than those of CdTe cores due to the spatial separation of the charge carriers in type-II QDs decreasing the oscillator strength, leading to the decrease of the wave function overlap.
1:Experimental Design and Method Selection:
The CdTe/CdSe type-II core/shell QDs were fabricated via the colloidal synthesis by continuous deposition of Cd and Se organometallic precursors onto CdTe core QDs.
2:Sample Selection and Data Sources:
CdO (
3:99%), Se (99%), and Te (99%) were used as precursors. List of Experimental Equipment and Materials:
Energy-dispersive X-ray (EDX) spectrometer (Model JOEL JSM-5610), X-ray diffractometer (Siemen, D5500), transmission electron microscope (TEM, Joel-JEM 1010), Jasco V-770 spectrometer (Varian), iHR550 spectrometer, He-Cd laser with wavelength l exc = 355 nm, home-built time-resolved PL system with l exc = 405 nm.
4:Experimental Procedures and Operational Workflow:
The synthesis process included two steps. The first step was the growth and purification of CdTe cores and the second step was the deposition of 1-5ML CdSe shell.
5:Data Analysis Methods:
The PL QY of the QDs were determined through comparison using a Rhodamine 6G standard organic dye.
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