Font Size: a A A

Study Of Thiol-induced Chemical Etching Of Gold Nanoclusters With Aggregation-Induced Emission

Posted on:2020-08-16Degree:DoctorType:Dissertation
Country:ChinaCandidate:J X WangFull Text:PDF
GTID:1361330575973150Subject:Chemistry
Abstract/Summary:PDF Full Text Request
Recently,aggregation-induced emission(AIE),as an intriguing strategy to enhance the luminescence of Au nanoclusters(NCs),has attacted tremendous attention.Studies of AIE-type Au NCs are on a preliminary stage whose complex surface/interfacial structures and emission mechanism are still far from complete.Rational control of the AIE of Au NCs is currently one of the key challenges.In this paper,using glutathione-protected Au NCs as a model,we studied pH-controllable emission from AIE-type Au NCs accompanied with a self-assembly/disassembly process with Au(?)-thiolate complexes.It was found that the solution pH could manipulate the self-assembled morphology of Au(I)-thiolate complex encapsulating AIE-type Au NCs,thereby generating varied AIE.The highest quantum yield(QY)could reach 14%.It was further found that a certain degree of crystallization of the Au(?)-thiolate shell occurred on the surface of the AIE-type Au NCs which results in forming a more compact and rigid shell,thereby generating strong AIE via the restriction of intramolecular vibration-and rotation-induced internal nonradiative relaxation pathways.Then,we further studied the structure of the Au(I)-thiolate ligand shell by the cysteine-induced etching of the AIE-type Au NCs.It is found that the aurophilic interactions might not have contributed to the formation of the rigid shell and the AIE of the Au NCs.On the other hand,the etching process involved the penetration of cysteine molecules through the Au(I)-thiolate assemblies surrounding the Au(0)core.The Au(?)-thiolate surroundings could serve as a pH-responsive "valve" to control cysteine to get access to and etch the embedded AuNCs.Based on the pH-sensitive etching process,an AIE-type Au NCs-based chemosensor for highly sensitive and selective detection of cysteine was constructed which exhibited an ultra-wide linear concentration range as wide as 9 orders of magnitude and an ultra-low LOD of 6.3 pM(S/N = 3).Moreover,by utilizing the etching of the AIE-type Au NCs,novel luminescent self-assembled structures of Au(?)-thiolate complexes were synthesized which exhibited the striking assembled morphologies' diversity and have potential for the bioimaging application.
Keywords/Search Tags:Gold Nanoclusters, Aggregation-Induced Emission, Thiol-Induced Chemical Etching, Au(I)-Thiolate Complexes
PDF Full Text Request
Related items