Improving the charge balance and performance of CdSe/ZnS quantum-dot light-emitting diodes with a sputtered zinc-tin-oxide electron-transport layer and a thermally evaporated tungsten-oxide charge-restricting layer

The charge carrier balance and performance of CdSe/ZnS quantum-dot light-emitting diodes (QD-LEDs) with a vacuum-deposited electron-transport layer (ETL) and carrier-restricting layer (CRL) were successfully improved. Optimizing the fabrication process of the reactively sputtered zinc-tin-oxide (ZTO...

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Bibliographic Details
Published in:Japanese Journal of Applied Physics 2019-10, Vol.58 (10), p.106502
Main Authors: Kim, Dong-Jin, Lee, Ho-Nyeon
Format: Article
Language:English
Subjects:
Cadmium selenides
Carrier injection
Charge injection
Current carriers
Current efficiency
Electron transport
Holes (electron deficiencies)
Light emitting diodes
Organic light emitting diodes
Quantum dots
Tungsten
Zinc sulfide
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Summary:The charge carrier balance and performance of CdSe/ZnS quantum-dot light-emitting diodes (QD-LEDs) with a vacuum-deposited electron-transport layer (ETL) and carrier-restricting layer (CRL) were successfully improved. Optimizing the fabrication process of the reactively sputtered zinc-tin-oxide (ZTO) ETL and adopting a thermally evaporated tungsten-oxide (WOx) CRL improved the electron-hole balance, thus leading to QD-LEDs with improved performance. Impedance spectroscopy analysis was successfully exploited in investigating charge carrier injection into each layer of the QD-LED and electron-hole recombination behaviors. The QD-LED with optimized ZTO ETL and without WOx CRL exhibited 2600 cd m−2 luminance and 3.2 cd A−1 current efficiency, and the QD-LED with both optimized ZTO ETL and a WOx CRL exhibited 3900 cd m−2 luminance and 5.1 cd A−1 current efficiency. These results imply a practical method for improving the electron-hole balance and performance of QD-LEDs, and provide a reliable technique for analyzing the carrier behavior of QD-LEDs.
ISSN:0021-4922
1347-4065
DOI:10.7567/1347-4065/ab3c77