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Optimized structure of silane-core containing host materials for highly efficient blue TADF OLEDs
Ist Teil von
Journal of materials chemistry. C, Materials for optical and electronic devices, 2017, Vol.5 (26), p.6570-6577
Erscheinungsjahr
2017
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
Three new derivatives containing silane cores,
viz.
9,9′,9′′-(((4-(pyridin-3-yl)phenyl)silanetriyl)tris(benzene-4,1-diyl))tris(9
H
-carbazole) (
SiCz3Py1
), bis(4-(9
H
-carbazol-9-yl)phenyl)bis(4-(pyridin-3-yl)phenyl)silane (
SiCz2Py2
), and 9-(4-(tris(4-(pyridin-3-yl)phenyl)silyl)phenyl)-9
H
-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 (EQE
max
) 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.
, sp
3
-hybridized) linkage core for developing a variety of high
T
g
host materials, particularly for blue TADF OLEDs.
Sprache
Englisch
Identifikatoren
ISSN: 2050-7526
eISSN: 2050-7534
DOI: 10.1039/C7TC01357D
Titel-ID: cdi_crossref_primary_10_1039_C7TC01357D
Format
–
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