Facile fabrication of CdS–poly(3-hexylthiophene) hybrid film with improved photo-current response for heterojunction solar cells

Abstract

CdS nanostructured thin films have been directly fabricated on indium-tin oxide (ITO) glass substrates through a one-step solvothermal process involving a cadmium nanocrystal layer and sulfur powder in N,N-dimethyl formamide (DMF). Poly(3-hexylthiophene) (P3HT) was then infiltrated into the CdS framework. The CdS film and the CdS–P3HT hybrid film were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), photoluminescence spectroscopy (PL) and UV-vis spectroscopy. CdS–P3HT hybrid film exhibited a wider absorption in the solar spectrum and stronger photo-current response and external quantum efficiency than a pure CdS and P3HT film. Hybrid solar cell devices have been constructed based on the CdS–P3HT hybrid film with structure ITO–CdS–P3HT–Au. The effects of sulfur sources, solvent and thickness of elemental cadmium films on the photovoltaic performance of CdS–P3HT hybrid solar cells were assessed.