Synthesis of Type II CdTe-CdSe Nanocrystal Heterostructured Multiple-Branched Rods and Their Photovoltaic Applications

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• 作者：Haizheng Zhong ; Yi Zhou ; Yi Yang ; Chunhe Yang ; Yongfang Li
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：May 3, 2007
• 年：2007
• 卷：111
• 期：17
• 页码：6538 - 6543
• 全文大小：380K
• 年卷期：v.111,no.17(May 3, 2007)
• ISSN：1932-7455

文摘

Novel type II CdTe-CdSe semiconductor nanocrystal heterostructures (SNCHs) with multiple-branched rodmorphology were synthesized by epitaxial growth of CdSe from CdTe nanocrystals in solution, and the SNCHswere characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), energy-dispersive spectrometry (EDS), and X-ray diffraction (XRD) analysis. The SNCHs are composed of a CdTecore and CdSe branches, and most of the heterostructured nanocrystals have about 10 branched rods withthickness of 3-5 nm and length of 10-30 nm. The absorption spectra of the SNCHs covered the wholevisible region from 380 to 780 nm with a distinct peak at 560~580 nm corresponding to the absorption ofCdSe nanocrystals. The quenching of the photoluminescence (PL) peak of the CdTe core was observed in theSNCHs, which indicates that photoinduced charge separation existed in the SNCHs. Furthermore, thephotovoltaic properties of the SNCHs were studied on the basis of the devices with single component of theSNCHs and with the blend of P3HT and the SNCHs. The device based on the SNCHs single componentshowed an open-circuit voltage (V_oc) of 0.40 V, a short-circuit current density (J_sc) of 0.018 mA/cm², fillfactor (FF) of 38%, and power convention efficiency () of 0.003% under the illumination of AM1.5, 100mW/cm², which is greatly improved in comparison with that of the homostructured semiconductor nanocrystals.For the hybrid P3HT/SNCHs device, the J_sc, V_oc, FF, and of the device reached 0.58 mA/cm², 0.63V, 43%,and 0.16% respectively.