Charge Transfer from Perovskite Quantum Dots to Multifunctional Ligands with Tethered Molecular Species

Abstract

Perovskite quantum dots (pQDs) are promising materials for optoelectronic and photocatalytic applications due to their unique optical properties. To enhance charge carrier extraction or injection, donor/acceptor molecules can be tethered to the pQD. These molecules must strongly bind to the ionic surfaces of pQDs without compromising colloidal stability. This is achieved by using multifunctional ligands containing a quaternary ammonium binding group for strong pQD surface attachment, a long tail group for colloidal stability, and a functional group near the pQD surface. Such pQDs with ferrocene-functionalized ligands show fast photoexcited hole transfer with near-unity efficiency. Density functional theory calculations reveal how ferrocene’s molecular structure reorganizes following hole transfer, affecting its charge separation efficiency. This approach can also be extended to photoexcited electron and energy transfer processes with pQDs. Therefore, this strategy offers a blueprint for creating efficient pQD–molecular hybrids for applications like photocatalysis.