A top–down strategy towards monodisperse colloidal lead sulphide quantum dots

• Published in: Nature communications Vol. 4; no. 1; p. 1695
• Main Authors: Yang, Jing, Ling, Tao, Wu, Wen-Tian, Liu, Hui, Gao, Min-Rui, Ling, Chen, Li, Lan, Du, Xi-Wen
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 2013; Nature Publishing Group
• Subjects: 639/638; 639/925/357/1017; Ablation; Humanities and Social Sciences; Lasers; multidisciplinary; Nanocrystals; Nanoparticles; Quantum dots; Science; Science (multidisciplinary); Surfactants; China
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms2637

Monodisperse colloidal quantum dots with size dispersions <10% are of great importance in realizing functionality manipulation, as well as building advanced devices, and have been normally synthesized via ‘bottom–up’ colloidal chemistry. Here we report a facile and environmentally friendly ‘top–down’ strategy towards highly crystalline monodisperse colloidal PbS quantum dots with controllable sizes and narrow dispersions 5.5%< σ <9.1%, based on laser irradiation of a suspension of polydisperse PbS nanocrystals with larger sizes. The colloidal quantum dots demonstrate size-tunable near-infrared photoluminescence, and self-assemble into well-ordered two-dimensional or three-dimensional superlattices due to the small degree of polydispersity and surface capping of 1-dodecanethiol, not only serving as a surfactant but also a sulphur source. The acquisition of monodisperse colloidal PbS quantum dots is ascribed to both the quantum-confinement effect of quantum dots and the size-selective-vaporization effect of the millisecond pulse laser with monochromaticity and low intensity. Quantum dots with a fine size dispersion offer attractive levels of functional control and manipulation. In this study, Yang et al . report an environmentally friendly top–down synthesis technique, based on laser irradiation of a polydisperse of lead sulphide nanocrystals.