Ag₂₂ Nanoclusters with Thermally Activated Delayed Fluorescence Protected by Ag/Cyanurate/Phosphine Metallamacrocyclic Monolayers through In‐Situ Ligand Transesterification

Abstract

The composition of protection monolayer exerts great influence on the molecular and electronic structures of atomically precise monolayer protected metal nanoclusters. Four isostructural Ag/cyanurate/phosphine metallamacrocyclic monolayer protected Ag22 nanoclusters are synthesized by kinetically controlled in‐situ ligand formation‐driven strategy. These eight‐electron superatomic silver nanoclusters feature an unprecedented interfacial bonding structure with diverse E‐Ag (E=O/N/P/Ag) interactions between the Ag13 core and metallamacrocyclic monolayer, and displays thermally activated delayed fluorescence (TADF), benefiting from their distinct donor‐acceptor type electronic structures. This work not only unmasks a new core‐shell interface involving cyanurate ligand but also underlines the significance of high‐electron‐affinity N‐heterocyclic ligand in synthesizing TADF metal nanoclusters. This is the first mixed valence Ag0/I nanocluster with TADF characteristic.

Self-Trapped, Thermally Equilibrated Delayed Fluorescence Enables Low-Reabsorption Luminescent Solar Concentrators Based on Gold-Doped Silver Nanoclusters

“…Such a fast ISC process makes the excited-state behavior of our NCs distinct from conventional organic TADF emitters (without spin–orbit coupling). , In general, there are two types of TADF emitters, which can be classified by their excited-state kinetics, including conventional organic compounds ( k ISC ∼ k S ) and organometallic complexes ( k ISC ≫ k S ). − Recently, metal NCs have emerged as a novel class of TADF emitters. − Owing to fast ISC/RISC rates ( k ISC > k RISC ≫ k S ) in our Au-AgNCs@PVP, the thermal equilibrium between the singlet and triplet states can be reached quickly before electronic-state transitions. In this case, the population of excited states is dictated by both Δ E ST and temperatures. , Therefore, the Δ E ST value can be determined by temperature-dependent PL lifetimes according to the Boltzmann-type equation, τ ( T ) = 3 + exp ( − Δ E S T k normalB T ) ( 3 τ T ) + ( 1 τ S ) exp ( − Δ E S T k normalB T ) where τ S and τ T represent the singlet and triplet lifetimes.…”