Bipolar hosts based on a rigid 9,10-dihydroanthracene scaffold for full-color electrophosphorescent devices
Journal
Israel Journal of Chemistry
Journal Volume
54
Journal Issue
7
Pages
942-951
Date Issued
2014
Author(s)
Abstract
Abstract Two bipolar hosts, CzDPO and CzDOxa , comprising a hole‐transporting carbazole and an electron‐transporting diphenyl phosphine oxide or oxadiazole with a saturated linker (9,10‐dihydroanthracene) have been synthesized and characterized. The saturated linker limited the effective extension of π conjugation, leading to high triplet energies ( E T =2.97–2.98 eV). The diastereomers with a rigid configuration provided an amorphous thin film with high thermal ( T d =415–444 °C) and morphological stability ( T g =188–224 °C). The high triplet energies and bipolar carrier transport characteristics (ambipolariy) of CzDPO and CzDOxa can facilitate exothermic energy transfer to the dopants and balance carrier injection/transport in the emission layers. As a result, they were utilized as universal hosts for various phosphorescent OLEDs (from blue to red), showing average external quantum efficiencies ( η ext =8.2–13.1 %) and low efficiency roll‐off. In addition, we also fabricated dual‐emitter white organic light‐emitting diodes with a co‐doped single emissive layer. WOLED hosted by CzDOxa exhibited satisfactory device efficiencies (14.4 %, 25.7 cd A −1 , 27 lm W −1 ) with highly stable chromaticity (CIE x =0.26–0.28 and CIE y =0.38) at brightnesses from 560 to 15200 cd m −2 .
SDGs
Type
journal article