A new single-step technique to fabricate transparent hydrophobic surfaces utilizable in perovskite solar cells

We report a simple low-cost novel method for coating an ultrathin hydrophobic film usable for different applications. A hydrophobic layer is fabricated on a TiO 2 substrate by hydrolysis of silicone rubber evaporation. The hydrophobic Si (CH 3 ) 3 groups bonded to the substrate by the reaction of hydrophilic Si OH groups with the hydroxyl groups on the TiO 2 surface. In addition, the silicone film was introduced in a carbon-based perovskite solar cell as a tunneling passivation layer between the electron transport layer and the active layer to reduce interfacial and extraction losses. An improved perovskite layer with better crystallinity, larger grain size, and higher stability was achieved. The optimal energy conversion efficiency was 17.42% with FF, V OC, and J SC values of 73.76%, 1.1 V, and 21.39 mA cm −2, respectively.