Erlangen 2022 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 37: Quantum Optics (Miscellaneous) V

Q 37.2: Talk

Wednesday, March 16, 2022, 14:30–14:45, Q-H14

Fabrication of quantum light emitting diodes based on qiant shell quantum dots (GSQLED) — •Ekaterina Salikhova, Hendrik Schlicke, Jan-Steffen Niehaus, and Horst Weller — Fraunhofer CAN, Grindelallee 117, 20146 Hamburg, Germany

Colloidal semiconductor nanoparticles, so-called quantum dots (QDs), have several unique properties such as a narrow emission bandwidth and a high photoluminescence quantum yield. While QDs are used for photoluminescence-based color-conversion in TVs, there are still no commercial devices employing QLED (quantum light emitting diode) technology, where the QDs are driven by direct electronic charge injection. Quasi-type II quantum dots with a ’giant’ shells (GSQDs) show a good stability and near-unity photoluminescence quantum yields. When using these particles as emitter layer in QLEDs, high electroluminescence intensities and an improved device stability are expected. However, QLEDs based on such particles are rarely described in the literature. The hindered charge carrier injection when using GSQDs in QLEDs, especially green-emitting particles, is still a current challenge.

In this talk, the production of 1x1 cm² GSQLEDs based on red (CdSe/CdS, 11 nm diameter) and green (CdSe/Cd_0.5Zn_0.5S, 14 nm diameter) emitting GSQDs with a stack sequence ITO/PEDOT:PSS/ HTL/QDs/ZnO NP/Al is presented. The polymers PVC or TFB were used as hole transport layers (HTL). Through the use of the PVC, as well as a ligand exchange of the QDs’ native ligands with aminoethanol during an optimized layer production as part of the developed layer-by-layer process, the QLED properties were significantly improved.