Jeffrey Gorman (Durham University, Dept. of Chemistry)

Engineering exciton dynamics with DNA nanotechnology

Excited-state processes in molecular materials underpin technologies ranging from solar energy conversion to light emission and are now emerging platforms for quantum sensing. Central to these phenomena is the interplay between molecular structure, electronic coupling, and the resulting exciton dynamics. However, controlling intermolecular coupling with sufficient precision remains a longstanding challenge in synthetic chemistry.

Here, I will show how DNA nanotechnology provides a programmable platform for assembling molecular semiconductors with sub-nm control over their intermolecular spacing and electronic coupling. This enables well-defined molecular architectures in which fundamental excited-state processes can be isolated and investigated using ultrafast spectroscopy. I will demonstrate three examples we have explored covering charge transfer across donor-acceptor heterojunctions, symmetry-breaking charge transfer between identical semiconductors, and singlet fission, where a single photoexcited singlet exciton is converted into a correlated pair of triplet excitons. The latter has strong implications for solar light harvesting above the thermodynamic limit of single-junction solar cells, and as a potential qudit. Together, I will show how DNA assembly controls molecular organisation, which in turn governs electronic coupling and excited-state dynamics.

  1. Gorman, J.,* Orsborne, S., Budden, P., Sridhar, A., Greenfield, J.L., Congrave, D.G., Pandya, R., Liu, Y., Dowland, S., Ryan, S., Bronstein, H., Nitschke, J.R., Rao, A., Collepardo-Guevara,* R., Stulz, E.,* Auras, F.,* Friend, R.H.* “Exploring Size-Controlled Exciton Evolution Using DNA Libraries.” J. Am. Chem. Soc. 2026, 148 (8), 8893–8903. DOI: 10.1021/jacs.5c21113.
  2. Gorman, J.,† Hart, S.M.,† John, T., Castellanos, M.A., Harris, D., Parsons, M.F., Banal, J.L., Willard, A.,* Schlau-Cohen, G.S.,* Bathe, M.* “Sculpting Photoproducts with DNA Origami.” Chem 2024, 10 (5), 1553–1575. DOI: 10.1016/j.chempr.2024.03.007.
  3. Orsborne, S.R., Gorman, J., Weiss, L.R., Sridhar, A., Panjwani, N.A., Divitini, G., Budden, P., Palecek, D., Ryan, S.T., Rao, A., Collepardo-Guevara, R., El-Sagheer, A.H., Brown, T., Behrends, J., Friend, R.H.,* Auras, F.* “Photogeneration of Spin Quintet Triplet–Triplet Excitations in DNA-Assembled Pentacene Stacks.” J. Am. Chem. Soc. 2023, 145 (9), 5431–5438. DOI: 10.1021/jacs.2c13743.
  4. Gorman, J., Orsborne, S.R., Sridhar, A., Pandya, R., Budden, P., Ohmann, A., Panjwani, N.A., Liu, Y., Greenfield, J.L., Dowland, S., Gray, V., Ryan, S.T., De Ornellas, S., El-Sagheer, A.H., Brown, T., Nitschke, J.R., Behrends, J., Keyser, U.F., Rao, A., Collepardo-Guevara, R., Stulz, E., Friend, R.H.,* Auras, F.* “Deoxyribonucleic Acid Encoded and Size-Defined π-Stacking of Perylene Diimides.” J. Am. Chem. Soc. 2022, 144 (1), 368–376. DOI: 10.1021/jacs.1c10241.