Excited State Dynamics in Dual-Defects Modified Graphitic Carbon Nitride

Abstract

Significant efforts are focused on defect-engineering of metal-free graphitic carbon nitride (g-C 3 N 4 ) to amplify its efficacy. A conceptually new multidefect-modified g-C 3 N 4 having simultaneously two or more defects has attracted strong attention for its enhanced photocatalytic properties. We model and compare the excited state dynamics in g-C 3 N 4 with (i) nitrogen defects (N vacancy and CN group) and (ii) dual defects (N vacancy, CN group, and O doping) and show that the nonradiative recombination of charge carriers in these systems follows the Shockley−Read−Hall mechanism. The nitrogen defects create three midgap states that trap charges and act as recombination centers. The dual-defect modified systems exhibit superior properties compared with pristine g-C 3 N 4 because the defects facilitate rapid charge separation and extend the spectrum of absorbed light. The system doped with O shows better performance due to enhanced carrier lifetime and higher oxidation potential caused by a downshifted valence band. The study provides guidance for rational design of stable and efficient photocatalytic materials.

Morphology and Light‐Dependent Spatial Distribution of Spin Defects in Carbon Nitride

“…In light of photocatalytic applications, strategies have been developed to extend and enhance the absorption properties of CN towards the visible. These range from red‐ox chemical treatments, [12] to chemical doping with elements such as oxygen and sulphur[ 13 , 14 ] or by decoration and functionalisation of the scaffold with side groups. [15] However, all these modified forms of CN display an optical band gap spanning the region 2.50–2.75 eV and a similar C/N stoichiometric ratio.…”

Control of Charge Carrier Relaxation at the Au/WSe2 Interface by Ti and TiO2 Adhesion Layers: Ab Initio Quantum Dynamics

“…Here, electronic evolution is modeled using real-time TDDFT while classical MD describes the nuclear motions. The electron–nuclear interactions in charge relaxation processes are investigated using fewest-switches surface hopping (FSSH), , one of the most common NAMD methods, as implemented in the PYXAID code under the classical path approximation (CPA). , The methodology has been successfully applied to study excited-state dynamics in various nanoscale systems. − A more detailed description of the time–domain DFT and NAMD methods used can be found in the Supporting Information.…”

Morphology and Light‐Dependent Spatial Distribution of Spin Defects in Carbon Nitride

“…In light of photocatalytic applications, strategies have been developed to extend and enhance the absorption properties of CN towards the visible. These range from red‐ox chemical treatments, [12] to chemical doping with elements such as oxygen and sulphur [13, 14] or by decoration and functionalisation of the scaffold with side groups [15] . However, all these modified forms of CN display an optical band gap spanning the region 2.50–2.75 eV and a similar C/N stoichiometric ratio [12] .…”