Natural polysaccharide Konjac glucomannan (KGM) is, for the first time, applied as the polymer matrix for thin film gel electrolyte in CdS/CdSe quantum dot-sensitized solar cells (QDSCs). The predominance of this thin film quasi-solid state QDSCs lies in the in-situ preparation of the electrolyte and Cu2S counter electrode in one step without mold, which can significantly simplify the cell fabrication process. The cell based on this electrolyte presents an energy conversion efficiency of 4.0% under AM 1.5 illumination of 100 mW cm(-2) with excellent stability compared to that of liquid-based QDSCs. (C) 2012 Elsevier B.V. All rights reserved.