Large-area, flexible, and conductive porous films of interlinked carbon nanospheres for UV light filters and resistive heaters

Conductive and flexible thin films are promising for wearable electronic devices, but their fabrication is challenging due to their multiple requirements for structural and functional integration. Here, we present a chemical method for the preparation of large-area carbon films by <i>in situ</i> linking of uniform carbon nanospheres derived from stiff-shell polymeric crystals. The proof-of-concept interlinked carbon film features a dual-porous structure, consisting of intrinsic micropores within the nodes of carbon spheres and in-plane macropores within the interlinked carbon spheres patterned in mono-/few layers. The success in the preparation of such an interlinked carbon film relies on the unique combination of the liquid-solid configuration of the polymeric stiff-shell and soft-core, which induces a series of dynamic transformations from phase expansion, fusion, linking, and eventually forms large-area interlinked porous carbon nanospheres patterned in one layer. Such thin carbon films can be transferred onto various rigid or flexible substrates, and perform well as light filters that can block >90% UV light and as electrical-heating materials that delivered a heating efficiency up to 45.8 °C μm^-1. This work provides a smart engineering platform and benefits the design of future electronic skin and intelligent wearable devices.