Low-cost solution processed nano millet like structure CoS2 film superior to pt as counter electrode for quantum dot sensitized solar cells

• Published in: Electronic materials letters Vol. 11; no. 3; pp. 485 - 493
• Main Authors: Rao, S. Srinivasa, Punnosse, Dinah, Kim, Soo-Kyoung, Kim, Hee-Je
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Institute of Metals and Materials 01.05.2015; 대한금속·재료학회
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed Matter Physics; Materials Science; Nanotechnology; Nanotechnology and Microengineering; Optical and Electronic Materials; Original Article; 전자/정보통신공학; nano millet structure; counter electrode; quantum dot sensitized solar cells; chemical bath deposition; cobalt sulfide
• ISSN: 1738-8090; 2093-6788
• DOI: 10.1007/s13391-014-4158-7

Cobalt Sulfide (CoS 2 ) counter electrodes (CE) with uniform size distribution were obtained on fluorine-doped tin oxide (FTO) substrate as counter electrodes for polysulfide redox electrolyte in CdS/CdSe/ ZnS quantum dot-sensitized solar cells (QDSSCs) by chemical bath deposition (CBD) technique. In this study, we optimized the cobalt source, deposition temperature and time in the preparation of CoS 2 thin film to achieve greater conversion efficiency with strong adhesion on FTO. Relative to the platinum (Pt) electrodes, the CoS 2 electrode shows a higher catalytic activity, faster electron transport and lower chargetransfer resistance, which can play a role in rendering higher power conversion efficiency. As a result, QDSSCs with the optimized CoS 2 CE achieved a higher short-circuit current density of 13.08 mA cm -2 , open-circuit voltage of 0.47 V, fill factor of 0.34 and overall photovoltaic conversion efficiency of 2.17% obtained under one sun illumination (100 mW cm -2 ). Therefore, CoS 2 CE can be used as a promising CE in QDSSCs with efficiency exceeding that of high-cost Pt-based cells (1.64%).