In this work, we present a simple and solution-based synthesis approach to combine the virtues of PEDOT:PSS and carbon nanotube (CNT) by developing a composite film and their application as a hole selective layer (HSL) in organic-silicon hybrid heterojunction solar cell. The heterojunction solar cell with the optimised PEDOT: PSSCNT HSL showed a notable open-circuit voltage (V-oc) of 588.6 mV, short circuit current density (J(sc)) of 25.3 mA/cm(2) and fill factor (FF) of 60.79% yielding a photo-conversion efficiency (eta) of 9.05%. The pristine PEDOT:PSS/Si device obtained an eta of 6.2% with a Voc of 502 mV. The role of CNT in the charge transport mechanism and improving Voc was corroborated by employing various characterisation methods such as J-V, C-V, and electrochemical impedance spectroscopy. The composite layer induced a strong inversion layer in silicon and enhanced the device performance. The application of PEDOT:PSS-CNT composite film is not limited to c-Si solar cells, but can also be used to fabricate flexible organic and perovskite solar cells.