title: Optical properties and exciton dynamics of alloyed core/shell/shell Cd(1-x)Zn(x)Se/ZnSe/ZnS quantum dots.
abstract: In this study we introduce a new method for the one-pot synthesis of core/shell/shell alloyed Cd1-xZnxSe/ZnSe/ZnS QDs and examine the effect of the shell coating on the optical properties and exciton dynamics of the alloy core. The photoluminescence (PL) quantum yield is greatly enhanced after shell growth, from 9.6% to 63%. The exciton dynamics were studied by time correlated single photon counting (TCSPC) and fit using integrated singular value decomposition global fitting (i-SVD-GF), which showed the biexponential observed lifetimes on the nanosecond time scale remain the same after shell growth. Using ultrafast transient absorption (TA) spectroscopy and SVD-GF, we have determined that surface passivation by ZnSe and ZnSe/ZnS shells reduces nonradiative recombination primarily on the picosecond time scale. These findings are helpful in directing the development of the next generation of QDs for biological labeling and other applications.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA.
authors.forename: Bob C
authors.initials: BC
authors.lastname: Fitzmorris
authors.forename: Ying-Chih
authors.initials: YC
authors.lastname: Pu
authors.forename: Jason K
authors.initials: JK
authors.lastname: Cooper
authors.forename: Yi-Fang
authors.initials: YF
authors.lastname: Lin
authors.forename: Yung-Jung
authors.initials: YJ
authors.lastname: Hsu
authors.forename: Yat
authors.initials: Y
authors.lastname: Li
authors.forename: Jin Z
authors.initials: JZ
authors.lastname: Zhang
mesh_terms: D000497:Alloys / Q000138:chemical synthesis / Q000737:chemistry*; D035843:Biomedical Research / Q000295:instrumentation*; D002104:Cadmium / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D045663:Quantum Dots; D012643:Selenium / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D000497:Alloys; D011108:Polymers; D013440:Sulfides; D017967:Zinc Compounds; D002104:Cadmium; D012643:Selenium; C031238:zinc sulfide