Highly efficient hybrid light-emitting device using complex of CdSe/ZnS quantum dots embedded in co-polymer as an active layer.
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.
Kang
Byoung-Ho
BH
School of Electrical Engineering and Computer Science, Kyungpook National University, 1370 Sankyuk-dong, Bukgu, 702-701 Daegu, South Korea.
Seo
Jun-Seon
JS
Jeong
Sohee
S
Lee
Jihye
J
Han
Chang-Soo
CS
Kim
Do-Eok
DE
Kim
Kyu-Jin
KJ
Yeom
Se-Hyuk
SH
Kwon
Dae-Hyuk
DH
Kim
Hak-Rin
HR
Kang
Shin-Won
SW
D019187:Cadmium Compounds / Q000737:chemistry*; D004867:Equipment Design; D008027:Light; D049449:Luminescence; D036103:Nanotechnology / Q000379:methods*; D055096:Optical Devices; D009943:Organophosphorus Compounds / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry*
D019187:Cadmium Compounds; D009943:Organophosphorus Compounds; D011108:Polymers; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; C044965:trioctyl phosphine oxide; C058667:cadmium selenide; C031238:zinc sulfide