title: Quantum-Dot Light-Emitting Diodes with Nitrogen-Doped Carbon Nanodot Hole Transport and Electronic Energy Transfer Layer.
abstract: Electroluminescence efficiency is crucial for the application of quantum-dot light-emitting diodes (QD-LEDs) in practical devices. We demonstrate that nitrogen-doped carbon nanodot (N-CD) interlayer improves electrical and luminescent properties of QD-LEDs. The N-CDs were prepared by solution-based bottom up synthesis and were inserted as a hole transport layer (HTL) between other multilayer HTL heterojunction and the red-QD layer. The QD-LEDs with N-CD interlayer represented superior electrical rectification and electroluminescent efficiency than those without the N-CD interlayer. The insertion of N-CD layer was found to provoke the Förster resonance energy transfer (FRET) from N-CD to QD layer, as confirmed by time-integrated and -resolved photoluminescence spectroscopy. Moreover, hole-only devices (HODs) with N-CD interlayer presented high hole transport capability, and ultraviolet photoelectron spectroscopy also revealed that the N-CD interlayer reduced the highest hole barrier height. Thus, more balanced carrier injection with sufficient hole carrier transport feasibly lead to the superior electrical and electroluminescent properties of the QD-LEDs with N-CD interlayer. We further studied effect of N-CD interlayer thickness on electrical and luminescent performances for high-brightness QD-LEDs. The ability of the N-CD interlayer to improve both the electrical and luminescent characteristics of the QD-LEDs would be readily exploited as an emerging photoactive material for high-efficiency optoelectronic devices.
authors.affiliation: Graphene Research Institute, Sejong University, Gwangjin-gu, Seoul 05006, Republic of Korea.
authors.forename: Young Ran
authors.initials: YR
authors.lastname: Park
authors.affiliation: UNIST Central Research Facilities (UCRF), UNIST, Ulsan 44919, Republic of Korea.
authors.forename: Hu Young
authors.initials: HY
authors.lastname: Jeong
authors.affiliation: Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Gwangjin-gu, Seoul 05006, Republic of Korea.
authors.forename: Young Soo
authors.initials: YS
authors.lastname: Seo
authors.affiliation: Materials and Life Science Research Division, KIST, Seongbuk-gu, Seoul 02792, Republic of Korea.
authors.forename: Won Kook
authors.initials: WK
authors.lastname: Choi
authors.affiliation: Graphene Research Institute, Sejong University, Gwangjin-gu, Seoul 05006, Republic of Korea.|Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Gwangjin-gu, Seoul 05006, Republic of Korea.
authors.forename: Young Joon
authors.initials: YJ
authors.lastname: Hong