Optimization of gold nanoparticle photoluminescence by alkanethiolation

Lai, Soon Onn; Tan, Hui Ru; Tok, Eng Soon; Chen, Yuhan; Ong, Bin Leong; Li, Min-Tsang; Chen, Yiyun; Chien, Fan‐Ching; Chen, Peilin; Margaritondo, G.; Hwu, Y.

doi:10.1039/c5cc01229e

Cited by 9 publications

(5 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, for n-mercaptoalkanoic acidexchanged AuNPs, quantum yield generally increases as the length of the carbon chain increases from 3 to 11 carbons (Figure 1E−I), suggesting that larger ligands yield more emissive AuNPs (Figure 2). This relationship between ligand size and particle Φ is consistent with several studies of visibleemitting AuNPs 30,31 and is likely dependent on the ability of larger ligands to exclude collisional quenchers and other nonradiative decay pathways (e.g., excluding solvent, vide infra).…”

Section: ■ Results and Discussionsupporting

confidence: 88%

Ligand-Mediated “Turn On,” High Quantum Yield Near-Infrared Emission in Small Gold Nanoparticles

et al. 2015

View full text Add to dashboard Cite

Small gold nanoparticles (∼1.4-2.2 nm core diameters) exist at an exciting interface between molecular and metallic electronic structures. These particles have the potential to elucidate fundamental physical principles driving nanoscale phenomena and to be useful in a wide range of applications. Here, we study the optoelectronic properties of aqueous, phosphine-terminated gold nanoparticles (core diameter = 1.7 ± 0.4 nm) after ligand exchange with a variety of sulfur-containing molecules. No emission is observed from these particles prior to ligand exchange, however the introduction of sulfur-containing ligands initiates photoluminescence. Further, small changes in sulfur substituents produce significant changes in nanoparticle photoluminescence features including quantum yield, which ranges from 0.13 to 3.65% depending on substituent. Interestingly, smaller ligands produce the most intense, highest energy, narrowest, and longest-lived emissions. Radiative lifetime measurements for these gold nanoparticle conjugates range from 59 to 2590 μs, indicating that even minor changes to the ligand substituent fundamentally alter the electronic properties of the luminophore itself. These results isolate the critical role of surface chemistry in the photoluminescence of small metal nanoparticles and largely rule out other mechanisms such as discrete (Au(I)-S-R)n impurities, differences in ligand densities, and/or core diameters. Taken together, these experiments provide important mechanistic insight into the relationship between gold nanoparticle near-infrared emission and pendant ligand architectures, as well as demonstrate the pivotal role of metal nanoparticle surface chemistry in tuning and optimizing emergent optoelectronic features from these nanostructures.

show abstract

Section: ■ Results and Discussionsupporting

confidence: 88%

Ligand-Mediated “Turn On,” High Quantum Yield Near-Infrared Emission in Small Gold Nanoparticles

et al. 2015

View full text Add to dashboard Cite

show abstract

“…The role of the self-assembled monolayer of the c(RGDyK)-MHDA ligand is to improve the stability of nanoparticles because longer carbon chain n-alkanethiolates have a stronger reactive binding probability to gold by decreasing the activation energy barrier for the S-H bond dissociation. 45,46 Concurrently, the nanoprobe also possesses an active tumor-targeting ability through the function of the arginine-glycine-aspartic acid (RGD) tripeptide, as it and its derivatives are widely reported for targeting the a v b 3 integrin in angiogenic vessels. 26 Once the probe was placed under mildly acidic conditions, a mimic of the tumor environment, the susceptible citraconic amide moieties hydrolysed to a positive surface potential from negative as its terminal functional group changes from a carboxylate anion to a protonated amine.…”

Section: Design and Synthesismentioning

confidence: 99%

pH-responsive targeted gold nanoparticles for in vivo photoacoustic imaging of tumor microenvironments

Lui

Tsoi

et al. 2019

Nanoscale Adv.

View full text Add to dashboard Cite

show abstract

“…13 In addition, photooxidation of the 16-MHDA/11-MUTAB-Au NDs UV-60 is minimized, since it is difficult for O 2 to penetrate into the Au NDs when they are capped with dense, long chained 16-MHDA molecules. 45…”

Section: Photobleaching and Radical Formationmentioning

confidence: 99%

Photoassisted photoluminescence fine-tuning of gold nanodots through free radical-mediated ligand-assembly

et al. 2016

View full text Add to dashboard Cite

In this study, we have developed a simple photoassisted ligand assembly to fine-tune the photoluminescence (PL) of (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide-capped gold nanodots (11-MUTAB-Au NDs). The 11-MUTAB-Au NDs (size: ca. 1.8 nm), obtained from the reaction of gold nanoparticles (ca. 3 nm) and 11-MUTAB, exhibited weak, near-infrared (NIR) PL at 700 nm with a quantum yield (QY) of 0.37% upon excitation at 365 nm. The PL QY of the Au NDs increased to 11.43% after reaction with 11-mercaptoundecanoic acid (11-MUA) for 30 min under ultraviolet (UV) light, which was accompanied by a PL wavelength shift to the green region (∼520 nm). UV-light irradiation accelerates 11-MUA assembly on the 11-MUTABAu NDs (11-MUA/11-MUTAB-Au NDs) through a radical-mediated reaction. Furthermore, the PL wavelength of the 11-MUA/11-MUTAB-Au NDs can be switched to 640 nm via cysteamine under UV-light irradiation. We propose that the PL of the Au NDs with NIR and visible emissions was originally from the surface thiol-Au complexes and the Au core, respectively. These dramatically different optical properties of the Au NDs were due to variation in the surface ligands, as well as the densities and surface oxidant states of the surface Au atoms/ions. These effects can be controlled by assembling surface thiol ligands and accelerated by UV irradiation.

show abstract

Optimization of gold nanoparticle photoluminescence by alkanethiolation

Cited by 9 publications

References 21 publications

Ligand-Mediated “Turn On,” High Quantum Yield Near-Infrared Emission in Small Gold Nanoparticles

Ligand-Mediated “Turn On,” High Quantum Yield Near-Infrared Emission in Small Gold Nanoparticles

pH-responsive targeted gold nanoparticles for in vivo photoacoustic imaging of tumor microenvironments

Photoassisted photoluminescence fine-tuning of gold nanodots through free radical-mediated ligand-assembly

Contact Info

Product

Resources

About