Optoelectronic properties and charge transfer dynamics in graphene quantum dot/Ir(III) nanocomposites: Enhancing photocatalytic performance through strategic BTF conjugate binding and end-capping variations

Abstract

The aim of this study is to analyze the optoelectronic properties and charge transfer kinetics in nanocomposites comprising graphene quantum dots (GQDs) and Ir(III) complexes, with a specific focus on their relevance in photocatalytic applications. The investigation explores how the extent of π-conjugation, variations in end-capping substituents, and the binding position of benzothiazole fluorene (BTF) conjugates influence the electronic structures. The results indicate that attaching GQDs alters the band gaps and results in different energy alignments. By adjusting the position of BTF conjugate binding and the end-capping substituent, optimal photocatalytic performance can be achieved. Binding the BTF conjugate at the para-position enhances electron injection into TiO2, thereby improving photocatalysis. Conversely, binding the BTF at the meta-position contributes to the regeneration of the ground state, leading to increased light absorption and photoelectric conversion. Furthermore, incorporating a BTF conjugate at the meta-position of the 2-phenyl pyridine ligand enhances light absorption and photoelectric conversion in the nanocomposites. These findings pave the way for further exploration of the effects of different conjugate binding positions and substituents on the overall properties and potential applications of these nanocomposites.