Dynamics of recombination: Via conical intersection in a semiconductor nanocrystal

Wei Tao Peng, B. Scott Fales, Yinan Shu, Benjamin G. Levine

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Conical intersections are well known to introduce nonradiative decay pathways in molecules, but have only recently been implicated in nonradiative recombination processes in materials. Here we apply excited state ab initio molecular dynamics simulations based on a multireference description of the electronic structure to defective silicon nanocrystals up to 1.7 nm in diameter to search for accessible nonradiative recombination pathways. Dangling bond defects are found to induce conical intersections between the ground and first excited electronic states of five systems of various sizes. These defect-induced conical intersections are accessible at energies that are in the visible range (2.4-2.7 eV) and very weakly dependent on particle size. The dynamic simulations suggest that these intersections are accessed 40-60 fs after creation of a defect-localized excitation. This ultrafast recombination is attributed to the fact that Jahn-Teller distortion on the first excited state drives the defect directly towards a conical intersection with the ground electronic state.

Original languageEnglish (US)
Pages (from-to)681-687
Number of pages7
JournalChemical Science
Volume9
Issue number3
DOIs
StatePublished - 2018

Bibliographical note

Funding Information:
We gratefully acknowledge support from the National Science Foundation under grant CHE-1565634. We acknowledge fruitful discussion with Rémi Beaulac.

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