Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
Design of carbazole-based platinum complexes with steric hindrance for efficient organic light-emitting diodes
Ist Teil von
Dalton transactions : an international journal of inorganic chemistry, 2023-10, Vol.52 (38), p.1367-13676
Ort / Verlag
Cambridge: Royal Society of Chemistry
Erscheinungsjahr
2023
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
The construction of platinum complexes with high steric hindrance is expected to suppress triple-triplet annihilation and π-π stacking to achieve high-performance organic light-emitting diodes (OLEDs) with low efficiency roll-off. Herein, two large steric hindrance platinum complexes (
N
-CzPhPtacac and
N
-CzCF
3
PhPtacac) were prepared by taking advantage of steric hindrance between the phenyl group on carbazole and the functional group (phenyl and trifluoromethyl substituted phenyl) at the 3-position of a pyridine moiety. Due to the similar electron cloud distribution and gap difference between the HOMO and LUMO, the two complexes showed similar orange-red emission peaks at 590 and 596 nm with high PL quantum yields of 90% and 92% and short excited state lifetimes of 2.77 and 3.08 μs in doped films, respectively. Consequently, OLEDs based on
N
-CzPhPtacac and
N
-CzCF
3
PhPtacac showed maximum external quantum efficiency (EQE
max
) values of 15.4% and 18.9%, respectively. Importantly, benefitting from the more stretched spatial configuration from the -CF
3
effect, the corresponding OLED exhibited a lower efficiency roll-off, with an EQE of 18.1% at 1000 cd m
−2
.
The construction of platinum complexes with high steric hindrance is expected to suppress triplet-triplet annihilation and π-π stacking to achieve high-performance organic light-emitting diodes (OLEDs) with low efficiency roll-off.