title: Controlled optical properties of water-soluble CdTe nanocrystals via anion exchange.
abstract: We report a study on anion exchange reaction of CdTe nanocrystals with S(2-) in aqueous solution under ambient condition. We found that the optical properties of CdTe nanocrystals can be well tuned by controlling the reaction conditions, in which the reaction temperature is crucially important. At low reaction temperature, the product nanocrystals showed blue-shifts in both absorption and PL spectra, while the photoluminescence quantum yield (PLQY) was significantly enhanced. When anion exchanges were carried out at higher reaction temperature, on the other hand, obvious red shifts in absorption and PL spectra accompanied by a fast increase followed by gradual decrease in PLQY were observed. On variation of S(2-) concentration, it was found that the overall kinetics of Te(2-) for S(2-) exchanges depends also on [S(2-)] when anion exchanges were performed at higher temperature. A possible mechanism for anion exchanges in CdTe NCs was proposed.
authors.affiliation: Department of Physical Chemistry, School of Science, Beijing University of Chemical Technology, Beijing 100029, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Physical Chemistry, School of Science, Beijing University of Chemical Technology, Beijing 100029, China. Electronic address: jiajg@mail.buct.edu.cn.
authors.forename: Jianguang
authors.initials: J
authors.lastname: Jia
authors.affiliation: Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. Electronic address: zhouxw66@iccas.ac.cn.
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Zhou
mesh_terms: D000838:Anions / Q000737:chemistry; D019187:Cadmium Compounds / Q000737:chemistry*; D007700:Kinetics; D049329:Nanostructures / Q000737:chemistry*; D055620:Optical Phenomena; D010316:Particle Size; D012995:Solubility; D013455:Sulfur / Q000032:analysis*; D013499:Surface Properties; D013691:Tellurium / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000838:Anions; D019187:Cadmium Compounds; D014867:Water; D013455:Sulfur; D013691:Tellurium; C028337:cadmium telluride
keywords: Anion exchange; CdTe nanocrystal; Optical property; Temperature