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Pyrrolo[1, 2‐a]quinoxaline‐Based Bipolar Host Materials for Efficient Red Phosphorescent OLEDs
Author(s) -
Patil Bhausaheb N.,
Lade Jatin J.,
Vadagaonkar Kamlesh S.,
Chetti Prabhakar,
Chaskar Atul C.
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201801817
Subject(s) - phosphorescence , phosphorescent organic light emitting diode , oled , quantum efficiency , triphenylamine , carbazole , materials science , optoelectronics , acceptor , photochemistry , diode , chemistry , fluorescence , nanotechnology , optics , physics , layer (electronics) , condensed matter physics
Novel bipolar host materials 4CBZ‐PQ , 3CBZ‐PQ and TPA‐PQ based on carbazole, triphenylamine as electron donors and pyrrolo[1, 2‐a]quinoxaline as an electron acceptor unit has been synthesized and characterized. Their photophysical, thermal and electrochemical properties have also been investigated. These structures show suitable frontier molecular orbital (FMO) energy levels and ensure good thermal and morphological stability. Amongst these bipolar host materials, 4CBZ‐PQ showed high T g (155.7 o C) and T d (160.7 o C) as well as good triplet energy (E T ) of 2.59 eV. Hence, phosphorescent organic light‐emitting diodes (PhOLEDs) were fabricated containing 4CBZ‐PQ , 3CBZ‐PQ and TPA‐PQ as host materials. 4CBZ‐PQ showed best EL performance with a turn‐on voltage of 2.6 V, a maximum brightness of 100388 cd/m 2 , a maximum current efficiency of 18.1 cd/A 1 , a maximum power efficiency of 12.9 lm/W and an external quantum efficiency of 15.1%. The RBY (red, brown and yellow) three‐color PhOLED with 4CBZ‐PQ as the host material showed maximum external quantum efficiency of 15.1% for the red device, indicating its potential utility as a host material for highly efficient PhOLEDs.