title: Structural band-gap tuning in g-C3N4.
abstract: g-C3N4 is a promising material for hydrogen production from water via photo-catalysis, if we can tune its band gap to desirable levels. Using a combined experimental and ab initio approach, we uncover an almost perfectly linear relationship between the band gap and structural aspects of g-C3N4, which we show to originate in a changing overlap of wave functions associated with the lattice constants. This changing overlap, in turn, causes the unoccupied pz states to experience a significantly larger energy shift than any other occupied state (s, px, or py), resulting in this peculiar relationship. Our results explain and demonstrate the possibility to tune the band gap by structural means, and thus the frequency at which g-C3N4 absorbs light.
authors.affiliation: Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109, USA. thonhauser@wfu.edu.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Zuluaga
authors.forename: Li-Hong
authors.initials: LH
authors.lastname: Liu
authors.forename: Natis
authors.initials: N
authors.lastname: Shafiq
authors.forename: Sara M
authors.initials: SM
authors.lastname: Rupich
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Veyan
authors.forename: Yves J
authors.initials: YJ
authors.lastname: Chabal
authors.forename: Timo
authors.initials: T
authors.lastname: Thonhauser