Ligand-modulated electron transfer rates from CsPbBr3 nanocrystals to titanium dioxide

In most perovskite nanocrystal (PeNC)-based optoelectronic and photonic applications, surface ligands inevitably lead to a donor-bridge-acceptor charge transfer configuration. In this article, we demonstrate successful modulation of electron transfer (ET) rates from all-inorganic CsPbBr3 PeNCs to mesoporous titanium dioxide films, by using different surface ligands including single alkyl chain oleic acid and oleylamine, cross-linked insulating (3-aminopropyl)triethoxysilane and aromatic naphthoic acid molecules as the ligand-bridge. We systematically investigated the ET process through time-resolved photoluminescence spectroscopy. Calculations verified the ligand-bridge barrier effect of the three species upon the ET process. Transient absorption measurements excluded carrier-delocalization effect of the naphthoic acid ligands and confirmed the bridge-barrier effect. Our work provides a perspective for composable and appropriate ligands design for diverse practical purposes.

Automated summary

This study successfully modulated the electron transfer rates from CsPbBr3 PeNCs to titanium dioxide films by using different surface ligands, and verified the ligand-bridge barrier effect through calculations. Transient absorption measurements confirmed the bridge-barrier effect, excluding carrier-delocalization effect of the naphthoic acid ligands. The research provides a perspective for designing composable and appropriate ligands for various practical purposes.