Open AccessHighly efficient hybrid light-emitting device using complex of CdSe/ZnS quantum dots embedded in co-polymer as an active layer
Author(s) -
Byoung Ho Kang,
Jun Seon Seo,
Sohee Jeong,
Jihye Lee,
Chang Soo Han,
Do Eok Kim,
Kyu-Jin Kim,
Se Hyuk Yeom,
Dae−Hyuk Kwon,
HakRin Kim,
Shin Won Kang
Publication year - 2010
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.018303
Subject(s) - quantum dot , materials science , electroluminescence , optoelectronics , polymer , active layer , luminous efficacy , light emitting diode , brightness , layer (electronics) , nanotechnology , optics , thin film transistor , composite material , physics
We propose a highly efficient hybrid light-emitting device (LED) with a single active layer where CdSe/ZnS quantum dots (QDs) are dispersed as a guest material in a conjugated polymer (co-polymer) matrix used for a host material. In our structure, the QDs act on light-emitting chromophores by trapping the migrating excitons in the co-polymer matrix via Förster energy transfer, and improve the charge balance within the co-polymer by trapping the injected electron carriers. Experimental results show that the electroluminescent properties highly depend on the doping density of the QDs within the co-polymer matrix, where the luminance as well as the external current efficiency are initially enhanced with increasing the concentration of the dispersed QDs in the co-polymer solution, and then such properties are degraded due to aggregation of the QDs. We can get the maximum brightness of 9,088 cd/m(2) and the maximum external current efficiency of 7.5 cd/A in mixing ratio of the QDs by 1.0 wt%. The external current efficiency is enhanced by over 15 times and the turn-on voltage is reduced in comparison with the corresponding values for a reference device that uses only a co-polymer as an active layer.