l-Cysteine assisted-synthesis of 3D In2S3 for 3D CuInS2 and its application in hybrid solar cells

Abstract

In this paper, the L-cysteine assisted-synthesis of 3D In₂S₃ for 3D CuInS₂ with a walnut-shape structure was reported and the 3D CuInS₂ was applied in hybrid solar cells (HPSCs) for the first time. In the first step, 3D In₂S₃ was synthesized via a solvothermal method, with L-cysteine as the sulphur source, forming uniform flowerlike hierarchical structures. In the second step, chalcopyrite 3D CuInS₂ with a walnut-shape hierarchical structure was produced, using 3D In₂S₃ as the template and with the corporation of Cu²⁺. Correlated factors in the reaction, such as the molar quantity of L-cysteine and the solvent, were adjusted to study the formation process of 3D CuInS₂. 3D CuInS₂ displayed a wide absorption range in UV-vis spectra and quenched the fluorescence of poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene) (MEH–PPV) effectively; therefore, it was applied to the fabrication of MEH–PPV/3D CuInS₂ solar cells, with a mixture of polymer and 3D CuInS₂ as the photoactive layer, for the first time, obtaining a PCE of 0.4% and confirming that 3D CuInS₂ could be applied in HPSCs successfully.