Introducing a Robust Flexible Conductive Hybrid: Indium Oxide-ParyleneC Obtained by Vapor Phase Infiltration

Hybrid materials are a merger of inorganic and organic materials and, as such, have the potential to outperform the characteristics and functionalities of conventional, that is, inorganic or organic materials. Consequently, various routes for their synthesis are being explored. However, despite the enormous recent progress in synthetic strategies, the pool of successfully hybridized materials is still very limited, thereby lowering their practical applicability since the functionality of the materials relies on the choice of the organic and inorganic constituents and their interplay. This work demonstrates the hybridization of indium oxide with ParyleneC upon vapor phase infiltration (VPI) of the metal-containing precursor trimethylindium into the polymer and its reaction with a counter precursor in its subsurface. We found that the choice of hydrogen peroxide instead of water vapor as the oxygen source substantially influences the hybrid material formation, resulting in a hybrid with an increased infiltration depth down to 300 nm, a narrower band gap, and stable sheet resistance values over a broad range of infiltration temperatures, from 135 to 210 °C. Electron microscopy and chemical analysis revealed the formation of indium oxide nanoparticles (NPs) within the ParyleneC with a capping layer of indium oxide. The flexible hybrid withstands at least 7000 bending events over a curvature with a radius of 5.5 mm. The redistribution of the NPs inside the polymer matrix upon bending even leads to a decrease of the electrical sheet resistance, which makes this flexible conductive hybrid (FCH) material opting for applications as robust flexible transparent electrodes.