A quasi-solid-state gel-electrolyte containing mesoporous silica nanoparticles (MSNs) capable of light-scattering is applied to plastic-based dye-sensitized solar cells (DSSCs). The MSNs based gel-electrolyte exhibits higher reflectance in the visible wavelength and contains nanometer-sized pores to facilitate the I-/I-3(-) ion diffusion and increase the ionic conductivity of the gel-electrolyte. Linear sweep voltammetry (LSV) measurements and electrochemical impedance spectra (EIS) are used to substantiate the explanations. Optimization on both the wa of MSNs and the I-2 concentration (i.e., 10 wt% of MSNs and 0.02 M of I-2) of the gel-electrolyte give the best cell performance with a light-to-electricity conversion efficiency (eta) of 5.45% under illumination of 100 mW cm(-2). A mechanism for enhanced efficiency is proposed regarding the role of MSNs. (C) 2013 Elsevier B.V. All rights reserved.