Surface-Engineering Enhanced Charge Injection and Recombination of Silver Nanoclusters in an Aqueous Medium

An effective way to enhance the charge injection and the radiative recombination within atomically precise nanoclusters (NCs) is proposed with Ag-29(BDT)(12) (BDT = 1,3-benzenedithiol) and Ag-29(BDT)(12)(TPP)(4) (TPP = triphenylphosphine) as models. Surface-engineering Ag-29(BDT)(12) with phosphine ligands can passivate the four naked Ag atom sites on the surface of Ag-29(BDT)(12) and circumvent the geometric packing limitation induced by the wide footprint of BDT, which endows Ag-29(BDT)(12)(TPP)(4) with enhanced electrochemical redox for improved charge injection as well as boosted photoluminescence (PL) and electrochemiluminescence (ECL) for enhanced radiative charge recombination. The surface-engineering process demonstrates a negligible effect on the charge-injection potentials as well as the excited state emission for PL and ECL. Ag-29(BDT)(12) and Ag-29(BDT)(12)(TPP)(4) can be injected with holes and electrons via similar electrochemical redox processes; both annihilation ECL and co-reactant ECL of Ag-29(BDT)(12) and Ag-29(BDT)(12)(TPP)(4) match well with their valence (VB) hole/conduction (CB) electron injection-related oxidative/reductive processes and are of similar wavebands with a maximum emission wavelength around 795 nm.

Automated summary

Surface-engineering of Ag-29(BDT)(12) with phosphine ligands enhances electrochemical redox for improved charge injection and boosts photoluminescence and electrochemiluminescence for enhanced radiative charge recombination, with negligible effect on the charge-injection potentials and the excited state emission. Both annihilation ECL and co-reactant ECL of Ag-29(BDT)(12) and Ag-29(BDT)(12)(TPP)(4) match well with their valence/conduction band-related oxidative/reductive processes and have similar emission wavelengths around 795 nm.