title: Emissive CdTe/ZnO/GO quasi-core-shell-shell hybrid quantum dots for white light emitting diodes.
abstract: Colloidal quantum dots (QDs) have been extensively studied for optoelectronic and biological applications due to their unique physical and optical properties. In particular, among the optoelectronics applications, the white light emitting diode (WLED) has great potential in flat panel displays and solid-state lighting. Herein, we demonstrate a novel, facile, and efficient technique for the synthesis of CdTe/ZnO/GO quasi-core-shell-shell hybrid quantum dots containing the CdTe core with multi shells of ZnO and graphene oxide (GO) and fabrication of WQDLEDs. The CdTe/ZnO/GO quasi-core-shell-shell QDs have a unique strong photoluminescence (PL) peak at 624 nm related to the CdTe core and new weak peaks at 382, 404, 422, and 440 nm due to conjugation with ZnO and GO. Also, in the electroluminescence (EL), multiple emission peaks are observed, which can be correlated to the recombination process inside the CdTe core and also recombination of electrons in the lowest unoccupied molecular orbital (LUMO) and LUMO+2 of GO and holes in the valence band (VB) of ZnO. The QDLEDs show clear white color emission with a maximum luminance value of about 480 cd m-2with Commission Internationale de l'Eclairage (CIE) color coordinates of (0.35, 0.28).
authors.affiliation: Materials and Life Science Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea. wkchoi@kist.re.kr and Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Korea.
authors.forename: Hong Hee
authors.initials: HH
authors.lastname: Kim
authors.affiliation: Nanophotonics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.
authors.forename: Joon-Suh
authors.initials: JS
authors.lastname: Park
authors.affiliation: Nanophotonics Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.
authors.forename: Il Ki
authors.initials: IK
authors.lastname: Han
authors.affiliation: Advanced Analysis Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.
authors.forename: Sung
authors.initials: S
authors.lastname: Ok Won
authors.affiliation: Materials and Life Science Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea. wkchoi@kist.re.kr.
authors.forename: Cheolmin
authors.initials: C
authors.lastname: Park
authors.affiliation: Center for Opto-Electronic Materials and Devices, Post-Silicon Semiconductor Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea. youngjei@kist.re.kr dkhwang@kist.re.kr and Department of Nanomaterials and Nano Science, Korea University of Science and Technology (KUST), Daejeon 34113, Korea.
authors.forename: Do Kyung
authors.initials: DK
authors.lastname: Hwang
authors.affiliation: Materials and Life Science Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea. wkchoi@kist.re.kr and Department of Nanomaterials and Nano Science, Korea University of Science and Technology (KUST), Daejeon 34113, Korea.
authors.forename: Won Kook
authors.initials: WK
authors.lastname: Choi