In this work, semi-transparent inverted polymer solar cells with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate; PEDOT:PSS) top electrodes were fabricated by spin-coating process. Poly(3-hexylthiophene; P3HT):[6,6]-phenyl -butyric acid methyl ester (PCBM) was used as a model material combination for a bulk heterojunction solar cell, because this material combination has been frequently studied, and its properties and performance have been well established. For enhancing the wetting of P3HT:PCBM blend film, different plasma etching conditions were tried. In addition, different high boiling point organic additives were tried to enhance the conductivity of PEDOT:PSS. The performance of solar cells with different fabrication conditions for the top electrode was compared. The best performance was obtained for Ar plasma etching to improve wetting of PEDOT:PSS and the addition of ethylene glycol to improve conductivity.