Because of outstanding optical properties and non-vacuum solution processability of colloidal quantum dot (QD) semiconductors, many researchers have developed various light emitting diodes (LEDs) using QD materials. Until now, the Cd-based QD-LEDs have shown excellent properties, but the eco-friendly QD semiconductors have attracted many attentions due to the environmental regulation. And, since there are many issues about the reliability of conventional QD-LEDs with organic charge transport layers, a stable charge transport layer in various conditions must be developed for this reason. This study proposes the organic/inorganic hybrid QD-LEDs with Cd-free InP QDs as light emitting layer and inorganic ZrO2 nanoparticles as electron transport layer. The QD-LED with bottom emission structure shows the luminescence of 530 cd m-2 and the current efficiency of 1 cd/A. To realize the transparent QD-LED display, the two-step sputtering process of indium zinc oxide (IZO) top electrode is applied to the devices and this study could fabricate the transparent QD-LED device with the transmittance of more than 74% for whole device array. And when the IZO top electrode with high work-function is applied to top transparent anode, the device could maintain the current efficiency within the driving voltage range without well-known roll-off phenomenon in QD-LED devices.
Bibliographical noteFunding Information:
H.Y.K. and Y.J.P. contributed equally to this work. This work was supported by the Industrial Strategic Technology Development Program (10045145, Development of high performance (>70 cm2 V-1s-1) chalcogenide TFT backplane and cadmium-free highly efficient (>30 cd/A) hybrid EL material/devices) funded by the Ministry of Trade, Industry and Energy (MOTIE, Korea).
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- light emitting diode
- quantum dot
ASJC Scopus subject areas
- Condensed Matter Physics
- Materials Science(all)