Dimension-controlled synthesis of CdS nanocrystals: from 0D quantum dots to 2D nanoplates.
The dimension-controlled synthesis of CdS nanocrystals in the strong quantum confinement regime is reported. Zero-, one-, and two-dimensional CdS nanocrystals are selectively synthesized via low-temperature reactions using alkylamines as surface-capping ligands. The shape of the nanocrystals is controlled systematically by using different amines and reaction conditions. The 2D nanoplates have a uniform thickness as low as 1.2 nm. Furthermore, their optical absorption and emission spectra show very narrow peaks indicating extremely uniform thickness. It is demonstrated that 2D nanoplates are generated by 2D assembly of CdS magic-sized clusters formed at the nucleation stage, and subsequent attachment of the clusters. The stability of magic-sized clusters in amine solvent strongly influences the final shapes of the nanocrystals. The thickness of the nanoplates increases in a stepwise manner while retaining their uniformity, similar to the growth behavior of inorganic clusters. The 2D CdS nanoplates are a new type of quantum well with novel nanoscale properties in the strong quantum confinement regime.
World Class University (WCU) Program of Chemical, Convergence for Energy & Environment (C2E2), School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744, Korea.
Jae Sung
JS
Son
Kunsu
K
Park
Soon Gu
SG
Kwon
Jiwoong
J
Yang
Moon Kee
MK
Choi
Junhyeong
J
Kim
Jung Ho
JH
Yu
Jin
J
Joo
Taeghwan
T
Hyeon
D019187:Cadmium Compounds / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry; D043942:Nanotubes / Q000737:chemistry*; D045663:Quantum Dots; D013440:Sulfides / Q000737:chemistry*
D019187:Cadmium Compounds; D013440:Sulfides; C034939:cadmium sulfide