General low-temperature reaction pathway from precursors to monomers before nucleation of compound semiconductor nanocrystals

• Published in: Nature communications 2016-08, Vol.7 (1), p.12223-12223, Article 12223
• Main Authors: Yu, Kui, Liu, Xiangyang, Qi, Ting, Yang, Huaqing, Whitfield, Dennis M., Y. Chen, Queena, Huisman, Erik J. C., Hu, Changwei
• Format: Article
• Language: English
• Subjects: 119/118; 140/131; Humanities and Social Sciences; multidisciplinary; Nanocrystals; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms12223

Little is known about the molecular pathway to monomers of semiconductor nanocrystals. Here we report a general reaction pathway, which is based on hydrogen-mediated ligand loss for the precursor conversion to ‘monomers’ at low temperature before nucleation. We apply 31 P nuclear magnetic resonance spectroscopy to monitor the key phosphorous-containing products that evolve from MX n + E =PPh 2 H+H Y mixtures, where MX n , E =PPh 2 H, and H Y are metal precursors, chalcogenide precursors, and additives, respectively. Surprisingly, the phosphorous-containing products detected can be categorized into two groups, Ph 2 P– Y and Ph 2 P( E )– Y . On the basis of our experimental and theoretical results, we propose two competing pathways to the formation of M 2 E n monomers, each of which is accompanied by one of the two products. Our study unravels the pathway of precursor evolution into M 2 E n monomers, the stoichiometry of which directly correlates with the atomic composition of the final compound nanocrystals. Little is known about the molecular pathway to monomers of semiconductor nanocrystals. Here, the authors report a general reaction pathway based on hydrogen-mediated ligand loss for the precursor conversion to ‘monomers’ at low temperature prior to nucleation, via 31 P NMR spectroscopic measurements.