Excited State Properties of Allylamine-Capped Silicon Quantum Dots

Excited-state properties of allylamine-capped silicon quantum dots (SiQDs) from Si 10 to Si 59 are studied using a density-functional tight-binding method and compared with available experimental data. Signatures in vibrational and optical absorption spectra are revealed, which show the detailed effect of modification of the SiQDs with allylamine. It is verified that the modification could be expected to not only reduce the surface oxidation rate but also maintain an efficient electronic transition feature that facilitates blue emission. The optical properties show significant size dependence due to the quantum confinement effect. The increase in the number of allylamine molecules could only result in a slight red shift of emission spectra.