Enhanced Fluorescence with Tunable Color in Doped Diphosphine-Protected Gold Nanoclusters

Abstract

Rational control of the luminescent properties of ligand-protected coinage metal clusters has long been pursued but remains challenging. Here we explore the crucial structural and electronic factors governing the fluorescence of a diphosphine-protected [Au 13 (dppe) 5 Cl 2 ] 3+ cluster by time-dependent density functional theory calculations. By substituting the central Au atom with group 5 to group 11 transition metal atoms, the emission wavelength is adjustable from red to blue, accompanied by enhanced fluorescence intensity compared with the undoped cluster. The evolution of light-emitting behavior upon doping and the corresponding roles of the dopant, Au cage, ligands, and their interplay are interpreted at the electronic structure level. In particular, strong dopant−Au cage interaction associated with large electron−hole overlap on the dopant are is a key factor to endow large emission energy and intensity. These theoretical results provide vital guidance for designing atomically precise nanoclusters with visible fluorescence and high quantum yield for practical uses.

Recent Advances in Long-Lived Emission in Coinage Metal Nanoclusters: Implications for Optoelectronic Applications

“…It was elucidated that the delayed green fluorescence is due to AIE of the aggregates of zinc ion complexed gold clusters. Jie She et al . explored the impact of doping on the luminescent characteristics of diphosphine-protected [Au 13 (dppe) 5 Cl 2 ] 3+ cluster.…”

“…It was elucidated that the delayed green fluorescence is due to AIE of the aggregates of zinc ion complexed gold clusters. Jie She et al104 explored the impact of doping on the luminescent characteristics of diphosphineprotected [Au 13 (dppe)5 Cl 2 ] 3+ cluster. The changes in lightemitting properties due to doping with group 5 to group 11 transition metal atoms, as well as the specific contributions of the dopant are elucidated by examining the electronic structure.…”

From 8- to 18-Cluster Electrons Superatoms: Evaluation via DFT Calculations of the Ligand-Protected W@Au12(dppm)6 Cluster Displaying Distinctive Electronic and Optical Properties

“…Thus, contrarily to [Au@Au 12 ] 5+ , the 5d AOs of the encapsulated atom are not nonbonding, but they constitute, after mixing with the 6s AOs of the cage, the occupied superatomic 1D bonding level, leading to the 1S 2 1P 6 1D 10 configuration. We have shown recently that a rather similar situation occurs in the hypothetical [Os@Au 12 (dppe) 5 Cl 2 ], featuring a 18-ce [Os@Au 12 ] core with promising high quantum yield fluorescent behavior . We investigate below, on the basis of relativistic density functional theory (DFT) calculations, the potential stability and optical properties of a 18-ce fully phosphine-protected neutral cluster containing the [W@Au 12 ] core that would be “isoelectronic” to the 8-ce cluster 1 , namely, [W@Au 12 (dppm) 6 ] ( 2 ).…”

“…We have shown recently that a rather similar situation occurs in the hypothetical [Os@ Au 12 (dppe) 5 Cl 2 ], featuring a 18-ce [Os@Au 12 ] core 62 with promising high quantum yield fluorescent behavior. 63 We investigate below, on the basis of relativistic density functional theory (DFT) calculations, the potential stability and optical properties of a 18-ce fully phosphine-protected neutral cluster containing the [W@Au 12 ] core that would be "isoelectronic" to the 8-ce cluster 1, namely, [W@Au 12 (dppm) 6 ] (2). The obtained results provide reliable models to establish the electron count−property relationship from ultrasmall clusters regime, contributing from fundamental aspects toward larger clusters.…”

Core-Packing-Related Vibrational Properties of Thiol-Protected Gold Nanoclusters and Their Excited-State Behavior

“…Gold nanoclusters (Au NCs), owing to their well-defined chemical composition and geometric structure, provide an ideal platform for exploring fundamental mechanisms − (e.g., stability, core-ligand interfacial effects, and emergence of the metallic states) as well as for developing technological applications − (e.g., biological diagnostics, optoelectronic devices, and catalysis). Unlike larger gold nanoparticles, ultrasmall Au NCs with diameters less than 2.2 nm exhibit strong quantum size effects, endowing them unique physicochemical properties including quantized energy levels, nonlinear optical behavior, and enhanced photoluminescence properties. − Among these properties, the optical properties and carrier lifetime of thiolate-protected Au NCs [Au n (SR) m ] have attracted extensive attention, primarily due to their atomic-level tunability achieved by modulating the size, composition, and shape of NCs. − …”