Pure Hydrocarbon Materials as Highly Efficient Host for White Phosphorescent Organic Light‐Emitting Diodes: A New Molecular Design Approach

Abstract

To date, all efficient host materials reported for phosphorescent OLEDs (PhOLEDs) are constructed with heteroatoms, which have a crucial role in the device performance. However, it has been shown in recent years that the heteroatoms not only increase the design complexity but can also be involved in the instability of the PhOLED, which is nowadays the most important obstacle to overcome. Herein, we design pure aromatic hydrocarbon materials (PHC) as very efficient hosts in high-performance white and blue PhOLEDs. With EQE of 27.7 %, the PHC-based white PhOLEDs display similar efficiency as the best reported with heteroatom-based hosts. Incorporated as a host in a blue PhOLED, which are still the weakest links of the technology, a very high EQE of 25.6 % is reached, surpassing, for the first time, the barrier of 25 % for a PHC and FIrpic blue emitter. This performance shows that the PHC strategy represents an effective alternative for the future development of the OLED industry.

Highly twisted bipolar molecules for efficient near-ultraviolet organic light-emitting diodesviaa hybridized local and charge-transfer mechanism

“…As a result, design of emitters for efficient NUV OLEDs is a considerable challenge. [25][26][27][28][29][30][31][32][33] On the other hand, the exciton utility of luminescent molecules is a significant factor for electroluminescence efficiency. For the reason of achieving theoretically the full use of excitons, thermally activated delayed fluorescence (TADF) emitters are widely used.…”

Regioselectivity Control in Spirobifluorene Nitration under Mild Conditions: Explaining the Crivello’s Reagent Mechanism

“…Spirobifluorene-based functional materials find application in many technological fields, such as solar cells, bioimaging, microporous polymers, and optoelectronics . Particularly, spirobifluorene derivatives have been investigated as high energy host materials for phosphorescent OLEDs . Moreover, 9,9′-spirobifluorene can also be used as the core of compounds showing peculiar optical properties, such as up-conversion and chiroptics .…”

Intra- vs Intermolecular Aurophilic Contacts in Dinuclear Gold(I) Compounds: Impact on the Population of the Triplet Excited State

“…This phenomenon is of great relevance for the preparation of novel devices, such as PhOLEDs, which are classified into the third generation of photodevices. They are able to harvest excitons from either the singlet or triplet energy states, which makes them more efficient than previous generations. − …”