In this manuscript, the effect of the 2-propanol(IPA)-treated poly(3,4-ethylenedioxy-thiophene): poly( styrenesulfonate) (PEDOT:PSS) on the performance enhancement of polymer solar cells(PSCs) based on poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl) carbonyl]thieno[3,4-b]thiophenediyl]]: [6,6]-phenylC71-butyric acid methyl ester (PTB7:PC7IBM) investigated in respect of the device physics. For device fabricated with 2-propanol (IPA)-doped PEDOT:PSS, it has been observed that the short circuit current density (Jsc) increases from 14.48 mA/cm(2) to 16.53 mA/cm(2), while the fill factor (FF) increases from 67.6% to 73.1%. As the result, the power conversion efficiency (PCE) of PSCs increases from 7.24% to 9.06%, which demonstrates 25% improvement, along with good stability. The enhancement of performance of the PSCs is mainly attributed to the increased charge transportation rate, collection rate, and reduced bimolecular recombination due to the inducing of the IPA-treated PEDOT:PSS. (C) 2015 Elsevier B.V. All rights reserved.