Improved Device Performance of Polymer-CuInS2/TiO2 Solar Cells Based on Treated CuInS2 Quantum Dots

This paper describes a solvothermal approach to remove the organic amine ligand on the surface of CuInS2 quantum dots (QDs) and demonstrates improved device performance of ternary polymer-CuInS2/TiO2 solar cells. Surface treatment of the CuInS2 QDs was carried out using different treatment methods, agents, and reaction times. Results showed that most of the amine ligands could be removed using hexanoic acid as the treatment agent by the solvothermal method in 16 h; the treated CuInS2 QDs displayed an aggregation tendency and quenched the fluorescence of poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene) (MEH-PPV) more effectively. As a result, MEH-PPV-CuInS2/TiO2 solar cells based on the treated CuInS2 QDs showed much higher device performance than those containing pristine CuInS2 QDs, achieving efficiency of 2.02% under AM1.5 illumination.