Stefan Seifermann

Towards Printed Organic Light-Emitting Devices: A Solution-Stable, Highly Soluble CuI–NHetPHOS

The development of iridium-free, yet efficient emitters with thermally activated delayed fluorescence (TADF) was an important step towards mass production of organic light-emitting diodes (OLEDs). Progress is currently impeded by the low solubility and low chemical stability of the materials. Herein, we present a CuI -based TADF emitter that is sufficiently chemically stable under ambient conditions and can be processed by printing techniques. The solubility is drastically enhanced (to 100 g L-1 ) in relevant printing solvents. The integrity of the complex is preserved in solution, as was demonstrated by X-ray absorption spectroscopy and other techniques. In addition, it was found that the optoelectronic properties are not affected even when partly processing under ambient conditions. As a highlight, we present a TADF-based OLED device that reached an efficiency of 11±2 % external quantum efficiency (EQE).

Soccer goes BOXing: synthetic access to novel [6:0] hexakis[(bisoxazolinyl)methano]fullerenes.

The syntheses of [6:0] hexakis[(bisoxazolinyl)methano]fullerenes are presented. Two derivatives could be directly obtained using conditions developed by the Sun group. For the remaining products, a two stage protocol had to be developed. All compounds we obtained in synthetically useful scales and were purified via column chromatography with standard achiral phase. These new fullerene adducts bear six metal-chelation sites which are aligned in the three orthogonal space directions and are disposed on a completely rigid scaffold. First experiments indicate that the generation of six-fold metal-complexes is possible with these structures. This makes them very appealing as ligands in asymmetric catalysis and as building blocks in higher supra-molecular assemblies.