Liquid junction solar cell (LJSC) with vertically silicon nanowires (SiNWs) as the primary photosensitizer, co-sensitized with luminescent and narrow gap CdTe nanoparticles, and cuboidal microstructures of zinc tetraphenyl porphyrin (ZnTPP) dye offers broad and intense visible light absorption that translates into a maximum power conversion efficiency (PCE) of 9.09%, when combined with a polymeric gel of a I2/I− redox couple as the hole transport material and a counter electrode (CE) of poly(3,4-ethyelenedioxythiophene) doped with imide ions (PEDOT-N(CF3SO2)2), under 1 sun irradiance. The p-type CdTe efficiently scavenges holes from SiNWs and simultaneously allows the passage of photoexcited electrons from ZnTPP to SiNWs via electrical conduction thus imparting an enhanced solar cell performance. Co-sensitization also supresses back electron transfer effectively, as is inferred from a ~68% enhancement in PCE compared to SiNWs alone. Optimization of the CE entailed the evaluation of the effect of dopant anion: imide versus dicyanamide in PEDOT, and revealed that the presence of macro-cracks in the polymer surface, a deeper work function, and a lower electrical conductance are the shortcomings of the dicyanamide doped PEDOT and reduce the overall PCE, compared to imide. This study brings out how by judicious choice of photoanode and CE components, efficient, stable and easy-to-assemble LJSCs can be developed. © 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences