Bi-containing reduced graphene oxide for CdTe solar cells. (August 2018)

• Record Type: Journal Article
• Authors: Bi, Xue; Luo, Guangcan; Li, Wei; Zhang, Jingquan; Wu, Lili; Li, Bing; Zeng, Guanggen; Wang, Wenwu
• Is Part Of: Solar energy. Volume 170(2018)
• Page Start: 820
• Page End: 827
• Publication Date: 2018-08
• Subjects: Bi/RGO composite -- Doping -- Back contact -- CdTe solar cells; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2018.05.084
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: Bi/RGO was prepared by a chemical reduction method using hydrazine hydrate. Bi/RGO was used as a back contact layer for the CdTe solar cells. Bi/RGO improves the hole collection ability, and supplies an active Bi diffusion source. Bi doping do not cause the deviation in composition from the stoichiometry for Bi/RGO. Abstract: Developing a good back contact material is important for high efficiency CdTe solar cells. In this work, the graphite oxide (GO) was prepared by the Hummers method through liquid oxidization, and the Bi-doping reduced graphene oxides (Bi@RGO) with different concentrations were synthesized by a chemical reduction of GO and BiCl3 aqueous solution using hydrazine hydrate. The doping concentration of bismuth was varied by controlling the mass ratio of GO/BiCl3 . The peaks of bismuth and RGO can be easily observed in the X-ray diffraction patterns. Both Raman spectra analysis and infrared spectra analysis also show that RGO is reduced successfully. Transmission electron microscopy shows Bi nanoparticles are entrapped inside the flake-like RGO. Furthermore, Bi-containing RGO/Au system was used as a back contact to CdTe thin film solar cells. The devices with Bi-containing RGO layers were fabricated and their photovoltaic characteristics such as short circuit current density, open circuit voltage, fill factor and efficiency were obtained. The results illustrate that Bi@RGO improves the hole collection ability, and supplies an active Bi diffusion source for the absorption layer, thereby enhancing CdTe solar cell performance.