Transparent Cu_1.8S and CuS thin films on FTO as efficient counter electrode for quantum dot solar cells

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• 作者：Shankara Sharanappa Kalanur ; Sang Youn Chae ; Oh Shim Joo ; ^{joocat@kist.re.kr} ; ^{joocat61@gmail.com}
• 关键词：Quantum dot solar cell ; Counter electrode ; Copper sulfide ; Hydrothermal method ; Polysulfide redox couple ; Charge-transfer resistance
• 刊名：Electrochimica Acta
• 出版年：2013
• 出版时间：30 July, 2013
• 年：2013
• 卷：103
• 期：Complete
• 页码：91-95
• 全文大小：1457 K

文摘

The use of metal sulfides as counter electrode (CE) improves the short circuit current, open circuit voltage, fill factor, and power conversion efficiency (¦Ç) of quantum dot solar cells (QDSCs) compared to the conventional Pt electrode. Here we demonstrate a simple hydrothermal method for the preparation of copper sulfide thin film on FTO, containing Cu_1.8S and CuS (Cu_1.8S/CuS) which can serve as efficient CE for QDSCs. Hydrothermal deposition of Cu_1.8S/CuS is carried out using thiourea as a source of sulfur and different copper salts as a source for copper. The product stoichiometry between Cu and S is observed to be dependent on the copper precursor. Under the illumination of one sun (100 mW cm^?2), the CdS-TiO₂ QDSCs incorporated with Cu_1.8S/CuS CE exhibits ¦Ç values of 1.66 % , which is much higher than the value 0.61 % obtained with Pt CE. Electrochemical impedance spectroscopy reveals low charge transfer resistance between polysulfide electrolyte and Cu_1.8S/CuS CE, indicating the high catalytic activity of Cu_1.8S/CuS CE. The results of this work show the potential application of hydrothermal synthetic method in making Cu_1.8S/CuS CE instead of Pt, for large-scale transparent QDSCs in the future.