Identification of Optical Transitions in Colloidal CdSe Nanotetrapods

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• 作者：Nguyen Xuan Nghia ; Le Ba Hai ; Nguyen Thi Luyen ; Pham Thu Nga ; Nguyen Thi Thuy Lieu ; The-Long Phan
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：December 6, 2012
• 年：2012
• 卷：116
• 期：48
• 页码：25517-25524
• 全文大小：454K
• 年卷期：v.116,no.48(December 6, 2012)
• ISSN：1932-7455

文摘

Though many different results associated with the optical properties of semiconductor nanotetrapods were reported, the relation between the spectral characteristics and change in energy offsets across core/arm interfaces of tetrapods has not been clarified yet. Particularly, the origin of an emission peaked at the high-energy region is still an issue of debate. To get more insight into these topical problems, we have studied systematically the optical properties of CdSe tetrapods synthesized with various precursor concentrations. Absorption and emission transitions in CdSe tetrapods were identified by means of their spectroscopic characteristics. We have identified the high-energy emission peak originating from spatially direct recombination of photogenerated carriers, which are located in the core of tetrapods. The relative-intensity increase of this emission is mainly related to an increase in the potential barrier for electrons and to a decrease in the potential barrier for holes. The differences in spectroscopic characteristics of CdSe tetrapods have also been further discussed in relation to their shape evolution in the one-pot synthesis.