Articles by Xuanwei Ong in JoVE
Facet-to-facet Linking of Shape-anisotropic Colloidal Cadmium Chalcogenide Nanostructures Xuanwei Ong*1, Shashank Gupta*1, Wen-Ya Wu2, Sabyasachi Chakrabortty1, Yinthai Chan1,3 1Department of Chemistry, National University of Singapore, 2Materials Processing and Characterisation Department, A*STAR, Institute of Materials Research and Engineering, 3Ceramics Department, A*STAR, Institute of Materials Research and Engineering A protocol detailing how shape-anisotropic colloidal cadmium chalcogenide nanocrystals can be covalently linked via their end facets is presented here.
Other articles by Xuanwei Ong on PubMed
Wet-Chemically Synthesized Colloidal Semiconductor Nanostructures As Optical Gain Media Chemphyschem : a European Journal of Chemical Physics and Physical Chemistry. Mar, 2016 | Pubmed ID: 26822201 An overview on the development of wet-chemically synthesized semiconductor nanostructures as optical gain materials is presented in this Review, beginning with the first demonstration of amplified spontaneous emission in zero-dimensional quantum dots and evolving to more sophisticated heterostructures such as one-dimensional core-seeded nanorods, branched core-seeded tetrapods and two-dimensional nanoplatelets. The advantages and challenges of utilizing strongly quantum-confined colloidal semiconductor materials as gain media are discussed, and a concerted effort is made to elaborate on how the progression towards more structurally complex architectures has allowed for dramatic improvements in performance and stability over the archetypal quantum dot.
Facet to Facet Linking of Shape Anisotropic Inorganic Nanocrystals with Site Specific and Stoichiometric Control Nano Letters. Oct, 2016 | Pubmed ID: 27607441 Nonclassical growth mechanisms such as self-assembly and oriented attachment are effective ways to build complex nanostructures from simpler ones. In the latter case, the nanoparticle components are electronically coupled; however, control over the attachment between nanoparticles is highly challenging and generally requires a delicate balance between dipole-, ligand-, and solvent-based interactions. To this end, we perform incomplete cation exchange with Ag(+) (Cu(+)) on CdSe-seeded CdS nanorods and tetrapods to exclusively convert their tips into small Ag2S (Cu2S) domains. Selective removal of the ligands from these inorganic domains results in spontaneous, site-specific bridging of the nanoparticles. Using this method, we demonstrate the fabrication of polymer-like linear and branched nanoparticles with enhanced electrical properties, as well as the stoichiometric formation of nanoparticle homo- and heterodimers and tetramers. We show that linked structures can then be completely cation exchanged with Pb(2+) to generate PbSe/PbS-based nanostructured photodetector media with enhanced properties.