We demonstrated for the first time that optically transparent and conductive polysiloxanes/PEDOT:PSS nanocomposite thin films were produced at 85 °C by mixing a sol–gel modified polysiloxane with the aqueous PEDOT:PSS solution. Polysiloxanes/PEDOT:PSS nanocomposite thin films were deposited by conventional solution-processed spin- or spray-coating methods, presenting superior water- and scratch-resistance. ∼100 Ω □⁻¹ sheet resistance with ∼80% transmittance was obtained and was further reduced to 25 Ω □⁻¹ by adding 90 nm ± 20 nm Ag nanowires to the solution. The p-type polysiloxanes/PEDOT:PSS nanocomposite thin films were then applied on n-type c-Si wafers to fabricate organic–inorganic Schottky hybrid photovoltaic devices, demonstrating a similar performance in power conversion efficiency as PEDOT:PSS. However, to the best of our knowledge our high conductive polysiloxanes/PEDOT:PSS nanocomposite c-Si hybrid photovoltaic devices presented the best stability among this type of devices under the ambient environment. Performance of our photovoltaic devices kept no degradation even if the devices were immersed in water without encapsulation for protection.