title: Crafting Core/Graded Shell-Shell Quantum Dots with Suppressed Re-absorption and Tunable Stokes Shift as High Optical Gain Materials.
abstract: The key to utilizing quantum dots (QDs) as lasing media is to effectively reduce non-radiative processes, such as Auger recombination and surface trapping. A robust strategy to craft a set of CdSe/Cd(1-x)Zn(x)Se(1-y)S(y)/ZnS core/graded shell-shell QDs with suppressed re-absorption, reduced Auger recombination rate, and tunable Stokes shift is presented. In sharp contrast to conventional CdSe/ZnS QDs, which have a large energy level mismatch between CdSe and ZnS and thus show strong re-absorption and a constrained Stokes shift, the as-synthesized CdSe/Cd(1-x)Zn(x)Se(1-y)S(y)/ZnS QDs exhibited the suppressed re-absorption of CdSe core and tunable Stokes shift as a direct consequence of the delocalization of the electron wavefunction over the entire QD. Such Stokes shift-engineered QDs with suppressed re-absorption may represent an important class of building blocks for use in lasers, light emitting diodes, solar concentrators, and parity-time symmetry materials and devices.
authors.affiliation: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
authors.forename: Jaehan
authors.initials: J
authors.lastname: Jung
authors.affiliation: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
authors.forename: Chun Hao
authors.initials: CH
authors.lastname: Lin
authors.affiliation: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Yoon
authors.affiliation: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
authors.forename: Sidney T
authors.initials: ST
authors.lastname: Malak
authors.affiliation: Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, 84112, USA.
authors.forename: Yaxin
authors.initials: Y
authors.lastname: Zhai
authors.affiliation: Department of Materials Science and Nanoengineering, Rice University, Houston, TX, 77251, USA.
authors.forename: Edwin L
authors.initials: EL
authors.lastname: Thomas
authors.affiliation: Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, 84112, USA.
authors.forename: Valy
authors.initials: V
authors.lastname: Vardeny
authors.affiliation: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Tsukruk
authors.affiliation: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA. zhiqun.lin@mse.gatech.edu.
authors.forename: Zhiqun
authors.initials: Z
authors.lastname: Lin
keywords: Auger recombination; CdSe quantum dots; Stokes shift; core/graded shell-shell quantum dots; optoelectronics