Improved performance from multilayer quantum dot light-emitting diodes via thermal annealing of the quantum dot layer

Yu Hua Niu, Andrea M. Munro, Yen Ju Cheng, Yanqing Tian, Michelle S. Liu, Jialong Zhao, Julie A. Bardecker, Ilan Jen-La Plante, David S. Ginger, Alex K Y Jen

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Abstract

The improvement in Quantum Dots (QD)-LED performance through improved polymer hole-injection layer (HIL)/hole-transport layer (HTL) structure and thermal annealing of the QD layer before the deposition of organic electron-transport layer was described. The polymer films were annealed for 15 minutes at different temperatures and the device was fabricated by evaporating electron-transporting small molecule to act as a cathode. The results show that the optimum annealing temperatures for the QD-LEDs correspond to 180°C and show improved spectral purity and enhanced enhanced efficiency after annealing. The decreased turn on voltage results from an increase in the current voltage showing that electrical transport through the polymer film is improved by annealing. Ligand desorption is found to improve charge injection and energy transfer from the organic semiconductors to the QDs by decreasing the thickness of the insulating surfactant shell surrounding each QD.

Original languageEnglish (US)
Pages (from-to)3371-3376
Number of pages6
JournalAdvanced Materials
Volume19
Issue number20
DOIs
Publication statusPublished - Oct 19 2007
Externally publishedYes

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ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Niu, Y. H., Munro, A. M., Cheng, Y. J., Tian, Y., Liu, M. S., Zhao, J., ... Jen, A. K. Y. (2007). Improved performance from multilayer quantum dot light-emitting diodes via thermal annealing of the quantum dot layer. Advanced Materials, 19(20), 3371-3376. https://doi.org/10.1002/adma.200602373