Molecular engineering of an electron-transport triarylphosphine oxide-triazine conjugate toward high-performance phosphorescent organic light-emitting diodes with remarkable stability

24.4: A Linear High‐Tg Arylphosphine Oxide‐Triazine Conjugate as a Doped Electron‐Transport Material for Stable Phosphorescent OLEDs

“…521 nm and CIE coordinates (0.31, 0.64). Differing from the previous reports [3,12] , CP045 acted as a light extraction layer instead. It showed an emissive peak at 531 nm with a narrow FWHM of 42 nm and CIE coordinates (0.256, 0.703).…”

“…Lowmolecular-weight ETMs that combine the advantages of facile synthesis and purification and enhanced electron mobility and glass transition temperature (Tg) have been tremendously desirable. Owing to the bulk, rigid and steric structure, bringing triarylphosphine oxide moieties to electron-deficient heterocyclic units provides a convenient route to organic glasses with electron-transport properties [2][3][4][5][6][7][8][9][10][11][12] . Through delicate molecular engineering, the resulting ETMs could be facilely available with high purity [3] , hence avoiding the residual halogen impurities long regarded as a key contributor to the OLED instability, arising from reactants or reaction intermediates [13][14][15] .…”

“…Owing to the bulk, rigid and steric structure, bringing triarylphosphine oxide moieties to electron-deficient heterocyclic units provides a convenient route to organic glasses with electron-transport properties [2][3][4][5][6][7][8][9][10][11][12] . Through delicate molecular engineering, the resulting ETMs could be facilely available with high purity [3] , hence avoiding the residual halogen impurities long regarded as a key contributor to the OLED instability, arising from reactants or reaction intermediates [13][14][15] . On the other hand, polaron-exciton annihilation creates a main source of degradation, in particular for phosphorescent OLEDs.…”

“…A top-emission green phosphorescent OLED that utilized TPO-Py-BPTRZ:50 wt% Liq as a single electron-transport layer revealed remarkable stability with lifetime t99  640 h @ 1000 cd m -2 . [3] In this contribution, we obtained a linearly conjugated triazine-based electron-transport material 6diphenylphosphinyl-6'-(4,6-diphenyl-1,3,5-triazin-2-yl)[2,2'binaphthyl] (DPO-2Na-TRZ) with an increased Tg of ca. 130.8 o C via Pd-catalyzed Suzuki coupling (Fig.…”

High‐Power‐Efficiency White Thermally Activated Delayed Fluorescence Diodes Based on Selectively Optimized Intermolecular Interactions

“…demonstrated a PO ETM, which dramatically improved device lifetime through balancing carrier flux. [ 13 ] Herein, in order to take an insight into the influence of intermolecular interactions in host matrices, we prepared two PO materials 2,4,6‐tri(diphenylphosphoryl)dibenzofuran (246DBFTPO) and 2,4,6,8‐tetra(diphenylphosphoryl)dibenzofuran (2468DBFQPO), respectively with three and four diphenylphosphine oxide (DPPO) substituents. Owing to the insulating effect of PO group, 246DBFTPO and 2468DBFQPO retain the optical properties of 46DBFDPO, for example, the first singlet (S 1 ) and triplet (T 1 ) energy levels of 3.9 and 3.0 eV, which avoids photophysical interferences in comparison.…”