A diarylborane-substituted carbazole as a universal bipolar host material for highly efficient electrophosphorescence devices

Abstract

Recently bipolar phosphorescent host materials have attracted wide attention since they can achieve better charge balance and hence better device performance. In this work, we report the synthesis and physical properties of a novel bipolar host material containing the dimesityl borane/carbazole hybrid, CMesB. With a high triplet energy, CMesB is considered a promising universal host material and has been applied to phosphorescent OLEDs of various colors. Red/green/blue/white (RGBW) OLEDs based on CMesB all show high external quantum efficiencies (20.7% for red, 20.0% for green, 16.5% for blue, and 15.7% for white) at practical brightnesses. The results indicate that the bipolar host CMesB with high triplet energy has high potential in manufacturing RGBW OLEDs for display or lighting applications.

Design and Development of Highly Efficient Light‐Emitting Layers in OLEDs with Dimesitylboranes: An Updated Review

“…first reported a high triplet energy bipolar phosphorescent host material, CMesB containing the dimesityl borane/carbazole hybrid, as shown in Figure . The CMesB‐based red/green/blue/white (RGBW) OLEDs exhibited high EQEs with red at 20.7 %, green at 20.0 %, blue at 16.5 %, and white at 15.7 % . A star‐shaped molecule BDDPC comprising a carbazole group and dimesitylborane groups was reported by Choi's group (Figure ).…”

Synthesis and Characterization of Oxazaborinin Phosphonate for Blue OLED Emitter Applications

“…In the last two decades, a number of materials have been developed and improved by both academic and industrial research to fulfil the requirements of these applications. [2][3][4][5][6][7][8][9][10][11][12] Intense effort has been devoted to developing materials and device structures for OLEDs in order to obtain higher efficiencies. Among the primary-colour luminescent materials for OLEDs, the blue emitters generally show a noticeably inferior electroluminescence (EL) performance with regard to efficiencies, lifespan, colour quality, and charge-carrier injection/transport.…”

“…Among the primary-colour luminescent materials for OLEDs, the blue emitters generally show a noticeably inferior electroluminescence (EL) performance with regard to efficiencies, lifespan, colour quality, and charge-carrier injection/transport. [4,[10][11][12] According to the standards of the fullcolour display industry, blue emitting materials should emit a saturated blue or deep-blue colour to meet the demand of high quality displays. This indicates that the blue emitters should possess a very wide band-gap, making it difficult to design their molecular structure.…”

Pyrrolo[1, 2‐a]quinoxaline‐Based Bipolar Host Materials for Efficient Red Phosphorescent OLEDs

“…In view of favorable triplet energy gap of 4CBZ‐PQ (2.59 eV), 3CBZ‐PQ (2.77 eV) and TPA‐PQ (2.69 eV), we selected 1,2,3,5‐tetrakis(carbazol‐9‐yl)‐4,6‐dicyanobenzene (4CzIPN), bis(2‐phenylpyridine)iridium(III)acetylacetonate (ppy) 2 Ir(acac), and bis(4’6’‐difluorophenylpyridinato) iridium(III) picolinate (Flrpic) as green and blue dopants for TPA‐PQ while osmium(II) bis(3‐trifluoromethyl)‐5‐(4‐ tert ‐butylpyridyl)‐1,2,4‐triazolate) dimethylphenylphosphine[Os(bpftz)2‐(PPhMe 2 ) 2 (OS1), tris(2‐phenylquinoline‐C 2 , N )iridium(III) (Ir(2‐phq) 3 ) and bis(2‐phenyl benzothiozolato‐ N ,C 2 ′)iridium(acetylacetonate) [( bt ) 2 Ir(acac)] are used as red, orange and yellow dopant for 4CBZ‐PQ as well as 3CBZ‐PQ .…”