Three-orders-of-magnitude variation of carrier lifetimes with crystal phase of gold nanoclusters

Abstract

Atomic packing controls exciton lifetime Like semiconductors, small metallic clusters can absorb light and create excitons (electron-hole pairs). In ligand-capped gold clusters of 30 to 40 atoms (Au 30 to Au 40 ) that adopt the usual face-centered cubic packing, the lifetime of these excitons is ∼100 nanoseconds. Zhou et al. found that atomic packing and molecular orbital overlap can greatly affect carrier lifetimes. Despite having similar bandgaps to those of face-centered cubic clusters, a hexagonal close-packed Au 30 cluster had a much shorter lifetime (∼1 nanosecond), and a body-centered cubic Au 38 cluster had a lifetime of ∼5 microseconds, which is comparable to bulk silicon. Science , this issue p. 279

Aggregation-induced emission in luminescent metal nanoclusters

“…vibration and rotation) of surface motifs, minimizing non-radiative decay [ 8 ]. Keeping this in mind, the AIE of metal NCs is, in essence, an affair closely related to the surface-emission state on the basis of ligand-to-metal charge transfer (LMCT) and/or ligand-to-metal-metal charge transfer (LMMCT), generating radiative relaxation via a metal-centered triplet [ 1 , 9 ]. Therefore, the AIE-type luminescent metal NCs feature long decay lifetime (μs-level), low emission energy (<2.2 eV) and large Stokes shifts (>100 nm), and their emission intensity is highly dependent on the features of their surface and interface [ 5 , 10 ].…”

Atomically precise metal nanoclusters meet metal-organic frameworks

“…Thus, NCs/MOF composites for PL applications require a thorough investigation in future work. Up to now, tens of metal NCs have been created ( Jin et al., 2016 ; Zhou et al., 2019 ), and more than 20,000 MOFs have been discovered, such as chiral MOFs ( Yoon et al., 2012 ), electrically conductive MOFs ( Xie et al., 2020 ), and luminescent MOFs ( Liu et al., 2020 ). These functionalized MOFs have been employed to optimize the functionalities of various guests for different applications.…”

“…The past decade has witnessed the rapid development of atomically precise metal nanoclusters (NCs), including the synthetic strategies and prospective applications ( Jin et al., 2016 ; Zhou et al., 2019 ). Particularly, NCs are of wide interest to the field of catalysis owing to their distinctive geometric and electronic structures ( Du et al., 2020 ; Jin et al., 2021a ).…”

Master key to coinage metal nanoclusters treasure chest: 38-metal clusters

“…In nanoclusters with less than 50 Au atoms, the optical properties are determined by their structure, and the effect of size on absorption, bandgap, and carrier lifetime are relatively small. 97–99…”