Polymer electrolytes based on poly(ethylene oxide) and ionic liquid (IL), 1-methyl 3-propyl imidazolium iodide (PMII) were prepared in film form by solution casting technique. Atomic force microscope (AFM) picture confirms the high surface roughness of films. The maximum ionic conductivity of the polymer/IL/I-2 electrolyte was 3.56 x 10(-4) S cm(-1) it room temperature. Doping of iodine in humid atmosphere formed 'fractal like structure' which affected ionic conductivity. The dye-sensitized solar cell (DSSC) using maximum ionic conductivity solid film at different humidity shows promising results. POLYM. ENG. SCI, 49:862-865, 2009. (C) 2009 Society of Plastics Engineers