Synthesis of distinctly thiol-capped CdTe quantum dots under microwave heating: multivariate optimization and characterization

• Type: Article in International Scientific Journal
• Date: 2017

Authors

Ribeiro, DSM (Author) Other; de Souza, GCS (Author) Other; Melo, A (Author) Other; Jose X Soares (Author) Other; Rodrigues, SSM (Author) Other; Araujo, AN (Author) FFUP; Montenegro, MCBSM (Author) FFUP; Joao L M Santos (Author) FFUP

Journal

Title: Journal of Materials Science

Vol. 52

Pages: 3208-3224

ISSN: 0022-2461

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 12 Citations

Scopus - 14 Citations

Other information

Authenticus ID: P-00M-B33

DOI: 10.1007/s10853-016-0610-4

Abstract (EN): The present work reports a straightforward one-step synthetic route assisted by microwave irradiation for the aqueous preparation of highly luminescence CdTe quantum dots capped with different ligands, namely, 3-mercaptopropionic acid (MPA), l-glutathione reduced and 2-mercaptoethanesulfonate. Utilization of microwave heating instead of convective heating, prevailing in the conventional hydrothermal synthesis, allows for rapid, uniform and controlled nucleation and growth of nanoparticles. Moreover, the use of air-stable Na2TeO3 as Te precursor enables a more user-friendly synthetic process averting the need for handling reagents in vacuum or under inert atmosphere. The experimental synthesis conditions for each capping were optimized by using a response surface methodology. The variables used for the optimization were the molar ratios of reagents and pH, and the optimization output was the highest photoluminescence quantum yield (QY). The optimal settings were determined by using a central composite design comprising a complete 2(3)-factorial design as cubic points, with six axial points at a distance of alpha = 1.682 from the design center and four center points. Additionally, the influence of the microwave irradiation time (2-90 min) and the reaction temperature (85-150 A degrees C) on the nanoparticles growth kinetics were thoroughly investigated. Under the optimized synthetic conditions highly luminescent (QY values up to approximately 60%), crystalline and monodisperse CdTe quantum dots with suitable surface functionalities were successfully obtained. The surface passivation with the respective capping ligand was characterized by FT-IR while the size and the high crystallinity of the as-prepared nanocrystals were confirmed by HR-TEM.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 17