The quinolinophenothiazine (QPTZ) fragment is a phenylacridine bridged by a sulphur atom. Despite appealing properties induced by this bridging (e.g. strong electron rich character), this fragment remains almost unexplored to...

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.

Nowadays, Phosphorescent Organic Light-Emitting Diodes (PhOLEDs) is a widespread technology, in which all the high-performance devices are constructed on a stack of different organic layers called multi-layer devices (ML-PhOLEDs). Thanks to these functional layers, the injection, the transport and the recombination of holes and electrons in the Emissive Layer (EML) are significantly improved allowing to reach high performances. In this technology, the ideal devices are the Single-Layer PhOLEDs (SL-PhOLEDs), with a very simple stack only constituted of the electrodes and the EML. These devices are simple, very easy to fabricate and can hence significantly decrease their costs. Nevertheless, removing the functional layers of an OLED drastically decreases the performances and there is, so far, only a few examples of high performances SL-PhOLEDs. Thus, in SL-PhOLEDs, the role of the functional layer should be done by the EML, which should allow an excellent injection, transport and recombination of holes and electrons. In this work, thanks to a rational molecular design of the EML, we report a green emitting SL-PhOLED displaying a very high external quantum efficiency of 22.7 %. The EML of this device is constructed on the barely studied Ir(ppy) 2 acac phosphor and a high efficiency host material possessing a Donor-spiro-Acceptor design. This performance is, to the best of our knowledge, the highest reported for SL-PhOLEDs (all colours considered). Through a structure/properties/device performance relationship study combining morphological (AFM), photophysical (time-resolved spectroscopy) and charge transport (SCLC) studies, we show that the EML presents all the required characteristics such as smooth surface, quick radiative deactivation and ambipolarity. In addition, the comparison with Ir(ppy) 3 , the most famous green emitter used in PhOLEDs highlights the high potential of Ir(ppy) 2 acac. The impact of the phosphorescent emitter on the ambipolarity of the charge transport is particularly evidenced.

Deep blue electroluminescence is highly required for organic light-emitting diode (OLED) technology. However, designing fluorophores displaying adequate CIE coordinates and particularly a low CIEy is far from an easy task....

In the last ten years, the development of -conjugated nanohoops has been considerable owing to their remarkable properties. However, to date, their incorporation in organic electronic devices remains very scarce. In this work, we report the first high performance organic electronic device (i.e. Phosphorescent Organic Light-Emitting Diode PhOLED) incorporating a nanohoop ([4]-cyclo-N-butyl-2,7-carbazole [4]C-Bu-Cbz), revealing their potential in electronics. Thus, using the red phosphor Ir(MDQ) 2 (acac), the [4]C-Bu-Cbz-based PhOLED displays a high External Quantum Efficiency (EQE) of 17.0 %, a Current Efficiency (CE) of 20.6 cd.A -1 and a Power Efficiency (PE) of 25.8 lm.W -1 demonstrating that the charges injection, transport and recombination are particularly efficient. This performance is significantly higher than that of its linear counterpart, N-butyl-2,7quartercarbazole [4]L-Bu-Cbz, which presents an EQE of 11.1 %, a CE of 13.0 cd.A -1 and a PE of 15.7 lm.W -1 . The significant difference, in term of device performance, between cyclic and acyclic compounds provides a new basis to construct high-performance electronic devices. This study, which includes optical, electrochemical, morphological and charge transport properties, shows that nanohoops can be efficiently used as organic semi-conductors in electronics and opens the way to their practical uses in highperformance optoelectronic devices, which is now the next stage of their evolution.