Green bottom-up synthesis of CdTe-MPA QDs induced by laser ablation. (August 2022)

• Record Type: Journal Article
• Authors: Silva, Stterferson E.; Freitas, Denilson V.; Navarro, Marcelo; Azevedo, Walter M.
• Is Part Of: Materials today communications. Volume 32(2022)
• Publication Date: 2022-08
• Subjects: Laser ablation, Bottom-up -- Semiconductors -- Nanoparticles -- Cadmium telluride; Materials science -- Periodicals; 620.11
• DOI: 10.1016/j.mtcomm.2022.104141
• Languages: English
• ISSNs: 2352-4928

Abstract

Abstract: CdTe quantum dots were synthesized in aqueous medium by a bottom-up method assisted by reactive laser ablation. In 3-mercaptopropionic acid and Cd 2+ solution (pH 10), elemental tellurium powder was used as target on the ablation process and reduced giving HTe - ions. CdTe seeds were immediately formed, and the modulation of the nanoparticle sizes was carried out by a post-synthesis heat treatment, when it was possible to evaluate the optical properties of the nanocrystals. The CdTe QDs showed luminescence between 524 and 650 nm (λexc = 488 nm), ranging from green to red. A maximum quantum yield of 28 % was obtained for 4.8 ± 0.8 nm nanoparticle average size, after 100 min of heat treatment. This new green methodology produces highly crystalline and low-polydispersity QDs, without the need of reducing agents and inert atmosphere. Graphical Abstract: ga1 Highlights: Laser ablation presents a green methodology, without the need of toxic strong reactive reducing agents, inert atmosphere or electrolytes. The production of HTe- ions, precursors of CdTe seeds, were obtained in 100 % yields using the RLAL method. Through the addition of MPA and post-synthesis heat treatment, it was possible to modulate the luminescence of the nanocrystals from green to red. Very stable and low-polydispersity CdTe colloidal suspensions were obtained, with quantum yields up to 28 %, with no undesirable byproducts.