Electron mobility determination of efficient phosphorescent iridium complexes with tetraphenylimidodiphosphinate ligand via transient electroluminescence method

Abstract

The electron mobility of Alq3 and iridium complexes was determined via transient electroluminescence (EL) method based on ITO (indium tin oxide)/di-[4-(N,N-ditolyl-amino)-phenyl]cyclohexane/complex/LiF/Al with short and rectangular driving voltage pulses. Apparent values of the electron mobility (μe) in complexes have been investigated from their onset of EL upon different driving voltages. The result reveals that the μe, 4.31 × 10−6 cm2/V·s, of the efficient phosphorescent material Ir(tfmppy)2(tpip) [1, tfmppy = 4-trifluoromethylphenylpyridine, tpip = tetraphenylimido-diphosphinate] under electric field of 1300 (V/cm)1/2 is as high as that of Alq3, which indicates that the good device performances of 1 are partly due to its high electron mobility.

Circularly polarised phosphorescent photoluminescence and electroluminescence of iridium complexes

“…Phosphorescent iridium complexes play an important role in efficient OLEDs because of their high quantum efficiency and short lifetime of triplet excited states 17 18 19 20 21 22 23 . In most cases, the popular Ir(III) complexes used in OLEDs are small molecules with a six-coordinate octahedral structure, such as homoleptic complexes fac -Ir(ppy) 3 (ppy = 2-phenylpyridine), heterogametic complexes Ir(ppy) 2 (acac) (acac = acetylacetonate) and FIrpic (iridium(III)bis[(4,6-difluoropheny)pyridinato- N , C 2 ) 17 24 25 26 27 .…”

Syntheses, Photoluminescence, and Electroluminescence of Iridium(III) Complexes with Fluorinated 2‐Phenylpyridine as Main Ligands and Tertraphenylimidodiphosphinate as Ancillary Ligand

“…To obtain phosphorescent OLEDs with low efficiency roll‐off, it is necessary to synthesize phosphorescent molecular materials with outstanding electron mobility. As discussed before, compared with the popular acac ligand, Htpip has more polar P=O bonds and four bulky aromatic groups, which may improve the electron mobility and suppress the TTA and TPQ effects effectively 8b…”

“…The electron mobility ( μ e ) values of the iridium complexes were determined by the transient electroluminescence (EL) method based on indium tin oxide (ITO)/ 1,1‐bis[4‐(di‐ p ‐tolyl‐amino)phenyl]cyclohexane (TAPC, 50 nm)/Ir complex (60 nm)/LiF (1 nm)/Al (100 nm) with short and rectangular driving voltage pulses 8b,17. In transient EL measurements, the time‐dependent EL response is monitored upon excitation of the devices with a rectangular voltage pulse.…”

“…Our group has reported highly efficient green and blue‐green phosphorescent OLEDs with tetraphenylimidodiphosphinate (tpip) derivatives as an ancillary ligand 8. Compared with the popular acac ligand, Htpip has more polar P=O bonds and four bulky aromatic groups, which may improve the electron mobility and lead to larger spatial separation of neighboring molecules of the Ir III complex to suppress triplet–triplet annihilation (TTA) and triplet–polaron quenching (TPQ) effectively 8b. The performances of the devices suggest that Htpip is a useful ancillary ligand for Ir III complexes and benefits OLED performances 8.…”

Tetraphenylimidodiphosphinate as solid phase extractant for preconcentrative separation of thorium from aqueous solution

“…Tetraphenylimidodiphosphinate (Htpip) is mainly applied to organic light-emitting diodes (OLEDs) [16,17], and Htpip with chemically bound chelating groups offer new possibilities for trace metal preconcentration. Hence, this paper reported tetraphenylimi-dodiphosphinate as solid phase extractant for preconcentrative separation of thorium.…”