Order Code: M2105A1
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General Information

CAS number 808142-23-6
Full name Bis[2-(diphenylphosphino)phenyl]ether oxide
Synonyms DPEPO
Chemical formula C36H28O3P2
Molecular weight 570.55 g/mol
Absorption λmax 388 nm in CH2Cl2
Fluorescence λem 311 nm in CH2Cl2
HOMO/LUMO HOMO = 6.1 eV, LUMO = 2.0 eV; T1 = 3.0 eV [1]
Classification / Family Diphenyl ether (DPE), TADF blue emitter host materials, Electron-transport layer materials (ETL), Hole-blocking layer materials (HBL), Phosphorescent organic light-emitting devices (PHOLEDs), Sublimed materials

Product Details

Purity Sublimed* >99.9% (HPLC)
Melting point TGA: >320 °C (0.5% weight loss)
Appearance White powder/crystals

*Sublimation is a technique used to obtain ultra pure-grade chemicals. For more details about sublimation, please refer to the Sublimed Materials for OLED devices page.


chemical structure of DPEPO
Chemical structure of  Bis[2-(diphenylphosphino)phenyl]ether oxide (DPEPO).



DPEPO, with steric ortho-substituted diphenylphosphine oxide (DPPO) groups, is one of the most popular large band-gap materials used to host blue TADF-based OLEDs.

This substitution with electron-withdrawing DPPO moieties not only improves its thermal and morphological stability, but also makes DPEPO an electron-transport layer material. Because of its deep HOMO energy level, DPEPO also acts as a hole-blocking layer material in TADF-OLED devices.


Device structure ITO/HATCN (5 nm)/NPB (30 nm)/TCTA (10 nm)/mCP (10 nm)/DMAC-DPS:PO-01* (0.8 wt% 30 nm)/DPEPO (10 nm)/Bphen (30 nm)/LiF (0.5 nm)/Al(150 nm) [2]
Colour White white
Max. EQE 20.8%
Max. Power Efficiency 51.2 lm/W
Device structure ITO (110 nm)/TAPC (35 nm)/mCBP (5 nm)/6 wt%-Ac-OSO:DPEPO (20 nm)/DPEPO (10 nm)/B3PyPB (40 nm)/LiF (0.8 nm)/Al (80 nm) [3]
Colour Blue blue
Max. Current Efficiency 37.9 cd/A
Max. EQE 20.5%
Max. Power Efficiency 20.1 Im/W
Device structure ITO/a-NPD (30 nm)/TCTA (20 nm)/CzSi (10 nm)/EML (20 nm)/ DPEPO (10 nm)/TPBI (30 nm)/LiF (0.5 nm)/Al [4]
Colour Blue blue
Max. EQE 14.5%
Max. Luminesence 2544 cd/m2
Device structure PEDOT:PSS (60 nm)/TAPC (20 nm)/mCP (10 nm)/DPEPO: TmCzTrz (25 nm)/TSPO1 (5 nm)/TPBI (20 nm)/LiF (1 nm)/Al (200 nm) [5]
Colour Blue blue
Max. EQE 25.5%
Max. Power Efficiency 52.1 Im/W

*For chemical structure information, please refer to the cited references.


Literature and Reviews

  1. Triplet exciton confinement in green organic light-emitting diodes containing luminescent charge-transfer Cu(I) complexes, Q. Zhang, et al., Adv. Funct. Mater.22, 2327–2336 (2012); DOI: 10.1002/adfm.201101907.
  2. Highly Efficient Simplified Single-Emitting-Layer Hybrid WOLEDs with Low Roll-off and Good Color Stability through Enhanced Förster Energy Transfer, D. Zhang et al., ACS Appl. Mater. Interfaces, 7 (51), 28693–28700 (2015); DOI: 10.1021/acsami.5b10783.
  3. High-Efficiency Blue Organic Light-Emitting Diodes Based on Thermally Activated Delayed Fluorescence from Phenoxaphosphine and Phenoxathiin Derivatives, S. Lee et al., Adv. Mater., 28, 4626–4631 (2016); DOI: 10.1002/adma.201506391.
  4. High-efficiency deep-blue organic light-emitting diodes based on a thermally activated delayed fluorescence emitter, S. Wu et al., J. Mater. Chem. C, 2,421 (2014); DOI: 10.1039/c3tc31936a.
  5. Design Strategy for 25% External Quantum Effi ciency in Green and Blue Thermally Activated Delayed Fluorescent Devices, D. Lee et al., Adv. Mater. 2015, 27, 5861–5867 (2015); DOI: 10.1002/adma.201502053.