Quinolinophenothiazine as an electron rich fragment for high efficiency RGB single-layer phosphorescent organic light-emitting diodes

Abstract

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...

Are pure hydrocarbons the future of host materials for blue phosphorescent organic light-emitting diodes?

“…44 This performance is the highest reported to date for a green single-layer-PhOLED (including heteroatoms-based hosts). As single-layer devices 2,8,11,20,29,48 only built with electrodes and EML are nowadays more and more appealing for the future of the OLED technology, this work also shows the real potential of PHC materials in this emerging technology. For more details on SL-PhOLEDs, see the recent review published in 2021.…”

“…28 This fragment has recently provided very high performance in simplified PhOLEDs. 29 Despite a high HOMO level and stable radical cation species, [28][29] this fragment suffers from the inversion of the nitrogen atom leading to diastereoisomeric features. 30 It is obvious that for the next step of the OLED technology, very simple molecular structures, which can be easily and cleanly synthesized, should be considered.…”

Spiro-configured dibenzosuberene compounds as deep-blue emitters for organic light-emitting diodes with a CIEy of 0.04

“…2(E)), this model compound displays a drastically different behaviour with a first oxidation wave that is only partially reversible and shifted to a higher The QPTZ building block is indeed known in the literature for the high stability of its cation radical and dication. 38 It should be noted that SF-DBS, when oxidized up to its second oxidation wave, is subjected to an electrodeposition process, involving carbon-carbon coupling at C2 of the fluorene units as usually observed for other fluorene based compounds. [45][46][47] However, no carbon-carbon coupling occurs on the DBS unit.…”

“…This is in accordance with the conclusions mentioned above in terms of wavelength emission. Thus, the sulphur bridge of the QPTZ fragment (which is a building unit only recently investigated for organic electronic applications [37][38][39] ) leads to very appealing electrochemical properties (a high HOMO and stability of the cation radical), but increases the non-radiative pathways. It is finally important to mention that no phosphorescence contribution is observed at 77 K in Me-THF for all compounds.…”

“…Herein, three emitters, SPA-DBS, SIA-DBS and SQPTZ-DBS, have been constructed following a similar molecular design strategy that is the spiro connection of an electron-rich unit, namely N-phenylacridine (PA), [33][34][35] indoloacridine (IA) 36 or quinolinophenothiazine (QPTZ) [37][38][39] to the DBS core. The PA, IA and QPTZ fragments are known to be efficient hole injecters due to their strong electron-rich character; in other words they possess high HOMO levels.…”