Hostname: page-component-77c89778f8-9q27g Total loading time: 0 Render date: 2024-07-16T20:27:37.432Z Has data issue: false hasContentIssue false

A step by step strategy for solution-processed quantum dots light emitting diodes

Published online by Cambridge University Press:  08 March 2011

Hélène Bourvon
Affiliation:
CEA-LETI, MINATEC Campus, DIHS/LTCV, 17 rue des Martyrs, 38054 Grenoble Cedex 9 France
Stéphanie Le Calvez
Affiliation:
CEA-LETI, MINATEC Campus, DIHS/LTCV, 17 rue des Martyrs, 38054 Grenoble Cedex 9 France
David Vaufrey
Affiliation:
CEA-LETI, MINATEC Campus, DIHS/LTCV, 17 rue des Martyrs, 38054 Grenoble Cedex 9 France
Sylvia Meunier Della Gatta
Affiliation:
CEA-LETI, MINATEC Campus, DIHS/LTCV, 17 rue des Martyrs, 38054 Grenoble Cedex 9 France
Get access

Abstract

Solution-based printing and coating processes have the potential to dramatically reduce the production costs of Organic Light Emitting Diodes. This is particularly true for Quantum Dots Light Emitting Diode (QDLEDs), the newborn in the field of LEDs, due to quantum dots price prohibiting wastage. Here, we report our latest results on the development of solutionprocessed QDLEDs. We have implemented a layer by layer strategy, from a whole evaporated small molecule based OLED to a hybrid QDLED developed by wet deposition techniques for the first layers and by evaporation for the last ones. Intermediate steps are discussed in this paper.

First, we have worked on a poly(3,4-ethylenedioxythiophene poly(styrenesulfonate) (PEDOT:PSS) layer. The PEDOT:PSS formulation for inkjet printing and spin coating were optimised: wettability on an ITO substrate, jettability of the inkjet formulation and baking conditions were studied. Additives as surfactant and ethylene glycol were added to the commercial inkjet grade solution to improve the deposition process. As a consequence to this study, anisotropic conductivity of PEDOT:PSS was observed and is reported here. In particular, ethylene glycol demonstrated a strong ability to increase the parallel conductivity by several orders of magnitude, but not the vertical one.

Then, inkjet-printed and spin-coated device performances are compared to complete this first study. Hybrid devices with an efficacy of 12cd/A at 4V were obtained, with 2.17 % of EQE, and a luminance of 4000 cd/m2 at 4V.

Finally, we succeeded in the development of our first QDLED based on CdSe core/ CdSZnS shell quantum dots emitting at a wavelength of 600nm. Quantum dots were inkjet printed, in order to waste as little as possible this very expensive material.

Type
Research Article
Copyright
Copyright © Materials Research Society 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Anikeeva, P.O., et al. ., Quantum dot light-emitting devices with electroluminescence tunable over the entire visible spectrum . Nano Letters, 2009. 9(7): p. 25322536.Google Scholar
2. Haverinen, H.M., Myllylä, R.A., and Jabbour, G.E., Inkjet printing of light emitting quantum dots . Applied Physics Letters, 2009. 94(7).Google Scholar
3. Ouyang, J., et al. ., On the mechanism of conductivity enhancement in poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) film through solvent treatment . Polymer, 2004. 45(25): p. 84438450.Google Scholar
4. Nardes, A.M., Janssen, R.A.J., and Kemerink, M., A morphological model for the solventenhanced conductivity of PEDOT: PSS thin films. Advanced Functional Materials, 2008. 18(6): p. 865871.Google Scholar