Ultrafast charge injection in silver-modified graphitic carbon nitride

Author(s): Emma K. Orcutt, Shelton J. Varapragasam, Zöe C. Peterson, Jessica M. Andriolo, Jack L. Skinner, Erik M. Grumstrup

Abstract

Graphitic carbon nitride (gCN) is a promising organic platform for driving light-activated charge-transfer reactions in a number of valuable photocatalytic cycles. A primary limitation of gCN as a photocatalyst is its short excited-state lifetime, which is mediated by a high density of trap and defect sites that result in rapid excited-state decay and low photocatalytic efficiency. To enhance the catalytic activity, gCN is often functionalized with a metal co-catalyst; however, the mechanism by which metal co-catalysts enhance the reactivity has not been clearly established. In this work, the excited-state dynamics of gCN and silver-modified gCN are compared using ultrafast transient absorption and time-resolved photoluminescence spectroscopies. In silver-modified gCN, an ultrafast spectral shift in the silver plasmon resonance provides direct spectral evidence of electron transfer from gCN to the silver nanoparticles. The electron-transfer rate is competitive with other non-radiative relaxation pathways, with electron-transfer yields approaching 50%, thus providing an effective strategy for mitigating losses associated with defects and trap sites.

Citation

Orcutt, E. K., Varapragasam, S. J., Peterson, Z. C., Andriolo, J. M., Skinner, J. L., & Grumstrup, E. M. (2023). Ultrafast Charge Injection in Silver-Modified Graphitic Carbon Nitride. ACS Applied Materials & Interfaces, 15(12), 15478–15485. https://doi.org/10.1021/acsami.2c22870