Communication: Non-radiative recombination via conical intersection at a semiconductor defect.

Localization of electronic excitations at molecule-sized semiconductor defects often precedes non-radiative (NR) decay, and it is known that many molecules undergo NR decay via conical intersection. Herein, we report the direct simulation of fast and efficient NR decay via a conical intersection at a known semiconductor defect. It is suggested that this silicon epoxide defect may selectively quench photoluminescence (PL) in small silicon nanocrystals (band gap > ~2.8 eV), and thus influence both the observed PL yield and PL energy of oxidized silicon nanocrystals.