title: Exciton Recombination, Energy-, and Charge Transfer in Single- and Multilayer Quantum-Dot Films on Silver Plasmonic Resonators.
abstract: We examine exciton recombination, energy-, and charge transfer in multilayer CdS/ZnS quantum dots (QDs) on silver plasmonic resonators using photoluminescence (PL) and excitation spectroscopy along with kinetic modeling and simulations. The exciton dynamics including all the processes are strongly affected by the separation distance between QDs and silver resonators, excitation wavelength, and QD film thickness. For a direct contact or very small distance, interfacial charge transfer and tunneling dominate over intrinsic radiative recombination and exciton energy transfer to surface plasmons (SPs), resulting in PL suppression. With increasing distance, however, tunneling diminishes dramatically, while long-range exciton-SP coupling takes place much faster (>6.5 ns) than intrinsic recombination (~200 ns) causing considerable PL enhancement. The exciton-SP coupling strength shows a strong dependence on excitation wavelengths, suggesting the state-specific dynamics of excitons and the down-conversion of surface plasmons involved. The overlayers as well as the bottom monolayer of QD multilayers exhibit significant PL enhancement mainly through long-range exciton-SP coupling. The overall emission behaviors from single- and multilayer QD films on silver resonators are described quantitatively by a photophysical kinetic model and simulations. The present experimental and simulation results provide important and useful design rules for QD-based light harvesting applications using the exciton-surface plasmon coupling.
authors.affiliation: Analytical Science Group, Samsung Advanced Institute of Technology, Suwon 443-803, Republic of Korea.|Department of Chemistry, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Taeho
authors.initials: T
authors.lastname: Shin
authors.affiliation: Device &System Research Center, Samsung Advanced Institute of Technology, Suwon 443-803, Republic of Korea.
authors.forename: Kyung-Sang
authors.initials: KS
authors.lastname: Cho
authors.affiliation: Analytical Science Group, Samsung Advanced Institute of Technology, Suwon 443-803, Republic of Korea.
authors.forename: Dong-Jin
authors.initials: DJ
authors.lastname: Yun
authors.affiliation: Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors.forename: Jinwoo
authors.initials: J
authors.lastname: Kim
authors.affiliation: Analytical Science Group, Samsung Advanced Institute of Technology, Suwon 443-803, Republic of Korea.
authors.forename: Xiang-Shu
authors.initials: XS
authors.lastname: Li
authors.affiliation: Analytical Science Group, Samsung Advanced Institute of Technology, Suwon 443-803, Republic of Korea.
authors.forename: Eui-Seong
authors.initials: ES
authors.lastname: Moon
authors.affiliation: Device &System Research Center, Samsung Advanced Institute of Technology, Suwon 443-803, Republic of Korea.
authors.forename: Chan-Wook
authors.initials: CW
authors.lastname: Baik
authors.affiliation: Device &System Research Center, Samsung Advanced Institute of Technology, Suwon 443-803, Republic of Korea.
authors.forename: Sun
authors.initials: S
authors.lastname: Il Kim
authors.affiliation: Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Republic of Korea.
authors.forename: Miyoung
authors.initials: M
authors.lastname: Kim
authors.affiliation: Device &System Research Center, Samsung Advanced Institute of Technology, Suwon 443-803, Republic of Korea.
authors.forename: Jun Hee
authors.initials: JH
authors.lastname: Choi
authors.affiliation: Analytical Science Group, Samsung Advanced Institute of Technology, Suwon 443-803, Republic of Korea.
authors.forename: Gyeong-Su
authors.initials: GS
authors.lastname: Park
authors.affiliation: Analytical Science Group, Samsung Advanced Institute of Technology, Suwon 443-803, Republic of Korea.
authors.forename: Jai-Kwang
authors.initials: JK
authors.lastname: Shin
authors.affiliation: Device &System Research Center, Samsung Advanced Institute of Technology, Suwon 443-803, Republic of Korea.
authors.forename: Sungwoo
authors.initials: S
authors.lastname: Hwang
authors.affiliation: Device &System Research Center, Samsung Advanced Institute of Technology, Suwon 443-803, Republic of Korea.
authors.forename: Tae-Sung
authors.initials: TS
authors.lastname: Jung