Electronically Coupled Gold Nanoclusters Render Deep-Red Emission with High Quantum Yields

Abstract

Electronic coupling can be used to tailor electronic states and optical properties of the luminophores. Therefore, electronically coupled systems would provide unique properties, which cannot be achieved by individual constituents. Here, electronically coupled gold nanoclusters (AuNCs) were prepared on the basis of organosilane grafting and a sol–gel-derived porous silica template. After prolonged drying, the formed AuNCs@silica composites exhibited red-shifted, line-width-narrowed, deep-red emission with high quantum yields (QYs) of ∼66% due to electronic-coupling-enhanced radiative rates and covalent-bonding-suppressed nonradiative relaxation. Meanwhile, the absorption maximum was slightly blue-shifted, leading to a large Stokes shift. All experimental findings revealed the formation of electronically coupled AuNC aggregates confined inside the nanopores and bonded to silica matrix. The mechanism is distinctly different from conventional aggregation-enhanced emission. Our work would provide great potential to engineer photophysical properties by controlling the packing modes.

Tailoring the SWIR emission of gold nanoclusters by surface ligand rigidification and their application in 3D bioimaging

“…In a different study, Huang et al attributed a strong red PL intensity of Au NCs loaded in a silica matrix to electronic-coupling-enhanced radiative rates and covalent-bonding-suppressed nonradiative relaxation. 27 The even longer 200 nm bathochromic shift of PL to 1450 nm which is reported here might be also associated to the surface modification but also a change of Au NC structure could happen during the casting process. With the red-shift and the enhancement of SWIR PL of this probe to the NIR-IIa region (1200–1400 nm) region in more complex environments, we are expecting high levels of detection at high concentrations in blood.…”

Highly efficient tandem luminescent solar concentrators based on eco-friendly copper iodide based hybrid nanoparticles and carbon dots

“…4,13 However, considering the large-scale production and practical usage and disposal, environmental contamination could be a major issue for these heavy-metal-containing QDs-based LSCs. Recently, a series of eco-friendly QDs were synthesized and employed as luminophores in LSCs, such as CuInS 2 /ZnS, 14,15 InP/ZnO, 16 silicon QDs, 6,17–19 carbon dots (CDs), 20–24 metal nanoclusters, 25–27 etc. Among them, CDs exhibited tunable emission spectra, wide absorption spectra, high PLQY, good photostability, and low cost, which make them considered a promising candidate as a luminophore for LSCs.…”

Two-Dimensional Self-Assembly of Boric Acid-Functionalized Graphene Quantum Dots: Tunable and Superior Optical Properties for Efficient Eco-Friendly Luminescent Solar Concentrators

“…Moreover, efficient PL can be also generated in an ambient light environment; thus, it would be beneficial to harvest both indoor room light and outdoor sunlight in an LSC operation. 67 To further study the origin of ultrahigh QY, temperaturedependent PL measurements were performed. Surprisingly, both PL spectra and time-resolved PL decay curves are nearly identical in the temperature range between 100 and 320 K, as shown in Figure 6a,b.…”

“…So far, most ultrahigh QYs were only achieved for the CNDs/GQDs with blue/green emission in dilute solution. , It is still challenging to attain an ultrahigh QY for the GQDs with long-wavelength PL, in particular, in the solid state, which would be very much beneficial for LSC application. Moreover, efficient PL can be also generated in an ambient light environment; thus, it would be beneficial to harvest both indoor room light and outdoor sunlight in an LSC operation …”