TY - JOUR
T1 - Optimized structure of silane-core containing host materials for highly efficient blue TADF OLEDs
AU - Choi, Suna
AU - Godumala, Mallesham
AU - Lee, Ji Hyung
AU - Kim, Gyeong Heon
AU - Moon, Ji Su
AU - Kim, Jun Yun
AU - Yoon, Dae Wi
AU - Yang, Joong Hwan
AU - Kim, Jinook
AU - Cho, Min Ju
AU - Kwon, Jang Hyuk
AU - Choi, Dong Hoon
N1 - Funding Information:
This research was supported by the National Research Foundation of Korea (NRF2012R1A2A1A01008797) and by the Key Research Institute Program (NRF20100020209). D. H. Choi is particularly thankful for the support from LG display Co. Limited (2015-2016)
Publisher Copyright:
© 2017 The Royal Society of Chemistry.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2017
Y1 - 2017
N2 - Three new derivatives containing silane cores, viz. 9,9′,9′′-(((4-(pyridin-3-yl)phenyl)silanetriyl)tris(benzene-4,1-diyl))tris(9H-carbazole) (SiCz3Py1), bis(4-(9H-carbazol-9-yl)phenyl)bis(4-(pyridin-3-yl)phenyl)silane (SiCz2Py2), and 9-(4-(tris(4-(pyridin-3-yl)phenyl)silyl)phenyl)-9H-carbazole (SiCz1Py3), were designed and synthesized. Carbazole as a donor and pyridine as an acceptor were tethered to tetraphenylsilane at different mole ratios. All three host materials showed high glass transition temperatures between 118 and 164 °C, which are different from those of the previous silane-based host materials (e.g., diphenyldi-o-tolylsilane (UGH-1), 1,4-bis(triphenylsilyl)benzene (UGH-2), and 1,3-bis(triphenylsilyl)benzene (UGH-3)). The triplet energies of these three hosts are observed at 2.85-2.90 eV, which is high enough for them to act as blue host materials in thermally activated delayed fluorescence organic light emitting diodes (TADF OLEDs). In particular, SiCz2Py2 and SiCz1Py3 hosted-TADF OLEDs demonstrated excellent performances, with a maximum external quantum efficiency (EQEmax) of 18.7 and 18.8%, respectively. Such good performances of SiCz2Py2 and SiCz1Py3 are originated by suppressing the non-radiative triplet decay and high reverse intersystem crossing (RISC) rate constant for efficient triplet to singlet up-conversion. This work demonstrates that tetraphenylsilane is a promising non-conjugate (i.e., sp3-hybridized) linkage core for developing a variety of high Tg host materials, particularly for blue TADF OLEDs.
AB - Three new derivatives containing silane cores, viz. 9,9′,9′′-(((4-(pyridin-3-yl)phenyl)silanetriyl)tris(benzene-4,1-diyl))tris(9H-carbazole) (SiCz3Py1), bis(4-(9H-carbazol-9-yl)phenyl)bis(4-(pyridin-3-yl)phenyl)silane (SiCz2Py2), and 9-(4-(tris(4-(pyridin-3-yl)phenyl)silyl)phenyl)-9H-carbazole (SiCz1Py3), were designed and synthesized. Carbazole as a donor and pyridine as an acceptor were tethered to tetraphenylsilane at different mole ratios. All three host materials showed high glass transition temperatures between 118 and 164 °C, which are different from those of the previous silane-based host materials (e.g., diphenyldi-o-tolylsilane (UGH-1), 1,4-bis(triphenylsilyl)benzene (UGH-2), and 1,3-bis(triphenylsilyl)benzene (UGH-3)). The triplet energies of these three hosts are observed at 2.85-2.90 eV, which is high enough for them to act as blue host materials in thermally activated delayed fluorescence organic light emitting diodes (TADF OLEDs). In particular, SiCz2Py2 and SiCz1Py3 hosted-TADF OLEDs demonstrated excellent performances, with a maximum external quantum efficiency (EQEmax) of 18.7 and 18.8%, respectively. Such good performances of SiCz2Py2 and SiCz1Py3 are originated by suppressing the non-radiative triplet decay and high reverse intersystem crossing (RISC) rate constant for efficient triplet to singlet up-conversion. This work demonstrates that tetraphenylsilane is a promising non-conjugate (i.e., sp3-hybridized) linkage core for developing a variety of high Tg host materials, particularly for blue TADF OLEDs.
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U2 - 10.1039/c7tc01357d
DO - 10.1039/c7tc01357d
M3 - Article
AN - SCOPUS:85022208132
SN - 2050-7526
VL - 5
SP - 6570
EP - 6577
JO - Journal of Materials Chemistry C
JF - Journal of Materials Chemistry C
IS - 26
ER -