We present the results on the effect of surface morphology and dispersion media on the properties of PEDOT:PSS/n-Si hybrid solar cell containing functionalized graphene (Gr). The hybrid solar cells based on SiNWs showed higher power conversion efficiency (PCE) compared to the planar based cells due to suppressing the carrier recombination and improving carrier transport efficiency. The PCE of hybrid solar cells could be improved by adding Gr into PEDOT:PSS. Different solvents including deionized (DI) water, ethylene glycol (EG), and isopropyl alcohol (IPA) were used as media for Gr dispersion. The best performance was obtained for the cell containing Gr dispersed in EG with a measured PCE of 7.33% and nearly 13% and 16% enhancement in comparison with the cells using Gr dispersed in IPA and DI water, respectively. The increase in PCE is attributed to improving the carrier-mobility, electrical conductivity, PEDOT crystallinity, and ordering.