Tetrahexcarbon (TH-carbon) was recently predicted to be a stable
two-dimensional semiconductor with an intrinsic direct band gap, making
it promising for practical applications in optoelectronic devices.
In this work, ab initio density functional theory
(DFT) calculations were performed in order to study the possibility
of manipulating the essential physical and chemical properties of
TH-carbon by fluorination, which significantly change the hybridization
states of carbon atoms. The phonon spectrum, ab initio molecular dynamics (AIMD) simulations, and elastic constants results
revealed that fluorinated derivatives of TH-carbon are dynamically,
thermally, and mechanically stable. Depending on the fluorine coverage,
we examined the tunability of the electronic band gap and the direct–indirect–direct
band gap transitions. We found that the phononic gap in TH-carbon
can be controlled by fluorination. A decrease in the specific heat
capacity was observed with increasing fluorine coverage, which is
useful for nanoscale engineering of heat management. The fluorination
is found to reduce the in-plane stiffness and Young’s modulus
but it increases the ultimate strength. These results suggest fluorination
would enable the ability to tailor TH-carbon material for several
interesting technological applications.