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Excited State Dynamics in Dual-Defects Modified Graphitic Carbon Nitride

Significant efforts are focused on defect-engineering of metal-free graphitic carbon nitride (g-C N ) to amplify its efficacy. A conceptually new multidefect-modified g-C N having simultaneously two or more defects has attracted strong attention for its enhanced photocatalytic properties. We model a...

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Bibliographic Details
Published in:The journal of physical chemistry letters 2022-02, Vol.13 (4), p.1033-1041
Main Authors: Gumber, Shriya, Agrawal, Sraddha, Prezhdo, Oleg V
Format: Article
Language:English
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Summary:Significant efforts are focused on defect-engineering of metal-free graphitic carbon nitride (g-C N ) to amplify its efficacy. A conceptually new multidefect-modified g-C N 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 N 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 N 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.
ISSN:1948-7185
1948-7185
DOI:10.1021/acs.jpclett.1c04152