Enhance the performance of dye-sensitized solar cells by Bi sub(2)Te sub(3) nanosheet/ZnO nanoparticle composite photoanode

• Published in: Journal of alloys and compounds 2016-09, Vol.680, p.373-380
• Main Authors: Wan, Kai, Wu, Fang, Dou, Yuanyao, Fang, Liang, Mao, Caiying
• Format: Article
• Language: English
• Subjects: Nanostructure; Performance enhancement; Photovoltaic cells; Scanning electron microscopy; Solar cells; Thermoelectricity; X-ray diffraction; Zinc oxide
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2016.04.124

Hexagonal Bi sub(2)Te sub(3) nanosheets with uniform morphology were facilely synthesized through a hydrothermal method at 180 degree C. X ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and selected area electron diffraction (SAED) were employed to characterize the Bi sub(2)Te sub(3) nanosheets. The results clearly indicate that uniform Bi sub(2)Te sub(3) nanosheets with a side length of 300-400 nm were obtained. Bi sub(2)Te sub(3) nanosheet/ZnO nanoparticle (Bi sub(2)Te sub(3) NS/ZnO NP) composite photoanodes were fabricated with Bi sub(2)Te sub(3) NS concentration in the range of 0-0.25 at.%. The effect of Bi sub(2)Te sub(3) NS contents in composite photoanode on the performance of dye-sensitized solar cells (DSSCs) was systematically investigated. The photocurrent density-voltage (J-V) characteristics indicate that the DSSCs with Bi sub(2)Te sub(3) NS/ZnO NP composite photoanode exhibit significantly improved photovoltaic performance. Typically, the highest energy conversion efficiency of 4.10% which is increased by 46.95% compared with that of the bare ZnO can be achieved in the DSSC with 0.15 at.% Bi sub(2)Te sub(3) NS embedding. The EIS results further confirm that a moderate amount of Bi sub(2)Te sub(3) NS in photoanode could not only improve the electrons transport and suppress the charge recombination rate, but also enhance the electron collection efficiency. Furthermore, the excellent thermoelectric performance of Bi sub(2)Te sub(3) NS in the photoanode could greatly increase the electron density and lower the temperature of the DSSCs effectively. All these results suggest that the Bi sub(2)Te sub(3) NS/ZnO NP composite photoanode could highly enhance the performance of the DSSCs.