The recent experimental synthesis
of 2D graphitic C3N5 has attracted a lot of
interest in its electronic and
optical properties and its comparison with other graphitic C3N4 and C3N3. To this end, we performed
density functional theory calculations using the accurate HSE06 functional
and estimated the corresponding electronic properties. From a comparative
study of the band structures of C3N3, C3N4, and C3N5, we found that
the electronic band gap decreases in the order 3.24 eV (C3N3) > 2.81 eV (C3N4) > 2.19
eV (C3N5) with an increase in the number of
nitrogen
atoms in the unit cell of these graphitic carbon nitrides. Further,
the strain dependency of the band structure of 2D g-C3N5 under uniaxial and biaxial strains is performed using the
same HSE-06 functional. We found a systematic decrease of band gap
as strain increases. Out of the two types of strains, the biaxial
strain has been found to be more efficient in modulating the band
gap. The effect of strain on the structure is also explored by analyzing
the bond lengths and bond angles as well as the charge density plots.
Furthermore, we found that at a biaxial strain of 20%, an interesting
structural rearrangement occurs in 2D g-C3N5, which results in a finite magnetic moment arising from the loss
of spin-degeneracy of electronic levels. Finally, by studying the
evolution of band gap, band alignments, and optical absorption as
a function of strain, we are able to predict that C3N5 with biaxial strain in the range of 12–14% can be
a promising photocatalyst in overall water-splitting with excellent
optical absorption in the visible light spectrum.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.