Chemical Transformation of Carboxyl Groups on the Surface of Silicon Carbide Quantum Dots

Silicon carbide quantum dots in the size range of 1-10 nm are in the center of interest with unique properties that makes them very promising biomarkers. A central requirement for this application is the control over the complex structure of the surface to enable further surface functionalization processes, which are crucial for drug delivery. In this paper, a temperature-dependent infrared and photoluminescence spectroscopy study, combined with ab initio modeling, is presented in order to reveal the chemical transformations of the surface termination groups. We found that at temperatures above 370 K, acid anhydride groups form by condensation of water between neighboring carboxyl groups. The presence of the anhydride groups reveals the proximity of the carboxyl groups and represents a new possibility of selective engineering of new hybrid materials involving silicon carbide quantum dots.