Regensburg 2022 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Poster 1
CPP 12.78: Poster
Montag, 5. September 2022, 18:00–20:00, P1
Towards efficient blue perovskite lead-halide nanocrystal light emitting diodes — •Tassilo Naujoks1, Adrian Hochgesang2, Christopher Kirsch3, Marcus Scheele3, Mukundan Thelakkat2, and Wolfgang Brütting1 — 1Institut für Physik, Universität Augsburg, Germany — 2Universität Bayreuth, Germany — 3Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Germany
The research focus for affordable solution-processed light-emitters has been shifted towards quantum-dot materials in recent years. High quantum yields (QY) even with inorganic nanocrystals (NC) capped by organic ligands have been achieved. One prominent, particularly highly luminescent type of NC is lead-halide perovskite with tunable colour by halide composition achieving near-unity QY.
While for red and green emitting NCs the quantum efficiency in the resulting LEDs is engineered to a satisfactory level, blue perovskite NCs are still underperforming. One issue with blue and therefore wider bandgap NCs lies in the very deep valence level. With that, hole injection into the NCs is significantly impaired. Here we present two approaches to enhance hole-injection into blue LHP NCs. The use of carbazole moieties either within the ligand on the NC surface or as a TCTA-doped polyvinyl-carbazole (PVK) polymeric hole transport layer increases the efficiency in perovskite NC LEDs. We propose that the carbazole group effectively blocks electrons, while its deep HOMO facilitates the injection into the similarly deep valence level of the blue perovskites.