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Layer Number-Dependent Enhanced Photoluminescence from a Quantum Dot Metamaterial Optical Resonator

Year: 2021

Journal: ACS Appl. Electron. Mater., Volume 3, JAN 26, page 468–475

Authors: Takekuma, Haruka; Leng, Junfu; Tateishi, Kazutaka; Xu, Yang; Chan, Yinthai; Ryuzaki, Sou; Wang, Pangpang; Okamoto, Koichi; Tamada, Kaoru

Organizations: JSPS KAKENHI in Japan [19H05627]

Keywords: quantum dots; self-assembly; exciton-surface plasmon coupling; photoluminescence; metamaterial; finite-difference time-domain method

High-density colloidal quantum dot (QD) thin films are promising materials for optoelectronic devices. Our experimental data revealed a unique layer number-dependent photo- luminescence (PL) from multilayered QDs on a gold substrate. Compared with the PL intensity of QDs on glass substrates, the PL intensity of CdSe/ZnS QD multilayers on the gold substrate was enhanced approximately 10-fold with 6 layers (film thickness: 42 nm). This phenomenon was simply and reasonably explained by an optical simulation using the finite-difference time-domain method with the effective medium approximation, where the light confinement effect of the high-refractive index QD film acting as a metamaterial optical resonator was considered together with a long-range exciton-surface plasmon coupling and mirror effects. This result explains the QD film properties from both quantum physics and optical metamaterial viewpoints. This finding is important for the design of high-luminescence thin-film displays composed of condensed QD films.