Red Carbon Thin Film: A Carbon–Oxygen Semiconductor with Tunable Properties by Amine Vapors and Its Carbonization toward Carbon Thin Films

The requirements for organic semiconductor materials and new methods for their synthesis at low temperature have risen over the last decades, especially due to concerns of sustainability. Herein, the synthesis of a carbon/oxygen molecular semiconductor thin film, which is promptly reactive toward amines, is presented. This allows for tuning the semiconductor properties and application as amine vapor sensors for a scope of analogous amines. The gas‐to‐solid phase reaction causes a significant change of the films’ optical properties, blue‐shifting the absorption and the photoluminescence spectra from the red to the near UV spectral range. The irreversible chemical reaction between the thin film and the amine vapor is also exploited for the preparation of nitrogen‐containing thin carbon films. The herein presented materials and methods will be of interest for gas sensing applications as well as for the development of tunable semiconductors and heteroatom‐doped thin films. The synthesis of molecular red carbon thin films is addressed in this work. The as‐prepared thin films show selective, irreversible response to a scope of amines that enable a wide change in fluorescence and bandgap. Eventually, the thermal treatment of these films enables to prepare carbonaceous coatings with tunable heteroatom content at low temperature.