A Ligand Exchange Route to Highly Luminescent Surface‐Functionalized ZnS Nanoparticles and Their Transparent Polymer Nanocomposites

Abstract

A facile ligand exchange approach for surface‐functionalized ZnS nanoparticles (NPs) with 5‐(2‐methacryloylethyloxymethyl)‐8‐quinolinol (MQ) is described. The MQ–ZnS NPs, with a cubic crystal structure, have the same diameter as ZnS NPs without MQ about 3.0 nm. The MQ–ZnS NPs exhibit strong fluorescence emission at about 500 nm and a high photoluminescence (PL) quantum yield (QY), up to 40%, with a decreasing ratio of MQ to ZnS NPs. The PL decay study reveals that the lifetimes of the different MQ–ZnS NPs with a single exponential decay are in the nanosecond time domain for emission at about 500 nm, which is obviously different from that of ZnS NPs with a biexponential decay for defect‐state emission at 420 nm. The functionalized MQ–ZnS NPs are successfully incorporated into the polymer matrix by in situ bulk polymerization to fabricate transparent bulk nanocomposites with good thermal stability and processability. Transmission electron microscopy results show that the NPs are uniformly dispersed in the polymer matrix without aggregation. The good PL properties of MQ–ZnS NPs are preserved in the bulk nanocomposites. It is observed that the nanocomposites have red‐shifted excitation and emission wavelengths compared with those of both the polymer matrix and MQ–ZnS NPs, possibly because of the cooperative interaction between MQ–ZnS NPs and the polymer matrix with blue emission.

Fabrication of fluorescent mesoporous silica nanoparticles with confined 8-hydroxyquinoline functionalized ZnS nanoparticles and their transparent polymer nanocomposites

“…in mesoporous silica, the solvent molecules still can penetrate into the channel of mesopores and quench the fluorescence of Znq 2 complex owing to their interaction. So the unexpected optical properties of HQ-ZnS-CMS may be attributed to the unconventional metaloquinolate complexes formed on the spherical surface of ZnS NPs in CMS with a steric confinement effect, which can reduce the attack of solvent molecules [46]. The lifetime decay dynamics of different hybrid samples were also studied.…”

“…In our previous studies, it has been shown that the HQ molecules can coordinate with the surface metal atoms of ZnS semiconductor NPs to form stable highly fluorescent hybrids. There may be a cooperative interaction of the optical properties between the semiconductor NPs and the unconventional metaloquinolate complexes formed on the spherical NPs surface with a steric confinement effect [46]. In this paper, we provided a facile strategy for the preparation of highly fluorescent ZnS-mesoporous silica hybrid NPs.…”

Exciton Coupling of Surface Complexes on a Nanocrystal Surface

“…[13][14][15][16][17] Therefore, the theories and methods of coordination chemistry, typically molecular orbital theory and ligand field theory, can be applied to predict, design, and discuss the properties of surface complexes. On the other hand, the NC surface may provide coordination fields that differ from those of normal complexes.…”

Functionalisation of Colloidal Transition Metal Sulphides Nanocrystals: A Fascinating and Challenging Playground for the Chemist

“…plastics was investigated [391][392][393] A further elegant route to surface-functionalized ZnS nanoparticles (NPs) to be embedded in polymer matrix was based on a facile ligand exchange approach of mercaptoethanol with 5-(2-methacryloylethyloxymethyl)-8-quinolinol (MQ) [278]. By exploiting in situ bulk polymerization, the functionalised MQ-ZnS NPs were successfully incorporated into the polymer matrix to fabricate transparent bulk nanocomposites with good thermal stability and processability.…”

“…The ligand exchange between the existing ligand and a new one is generally based on a two-step stripping route in which the existing ligand is replaced by the new once, typically displaying higher affinity and stronger binding to the targeted surface. Ligand exchange [6,195,211,222,240,251,255,[275][276][277][278][279][280][281][282][283][284] is required to replace insulating organic surfactants and allow charge transport in nanocrystal solids as well as to prepare water-soluble nanocrystals that target specific cellular sites.…”