A multifunctional phosphine oxide-diphenylamine hybrid compound as a high performance deep-blue fluorescent emitter and green phosphorescent host

Solvatochromic dual luminescence of Eu–Au dyads decorated with chromophore phosphines

Chromophore-containing phosphines produce highly solvatochromic gold(i) fluorophores. Their combination with red-emitting Eu centers offers a facile approach to dual emissive complexes with widely tunable luminescence characteristics.

Highly luminescent phosphine oxide-containing bipolar alkynylgold(iii) complexes for solution-processable organic light-emitting devices with small efficiency roll-offs

We report the synthesis of alkynylgold(iii) complexes with an electron-transporting phosphine oxide moiety in the tridentate ligand and hole-transporting triarylamine moieties as auxiliary ligands to generate a new class of phosphine oxide-containing bipolar gold(iii) complexes for the first time. Such gold(iii) complexes feature high photoluminescence quantum yields of over 70% in 1,3-bis(N-carbazolyl)benzene thin films with relatively short excited-state lifetimes of less than 3.9 μs at a 20 wt% dopant concentration. Highly efficient solution-processable organic light-emitting devices have been prepared with superior current efficiencies of up to 51.6 cd A^-1 and external quantum efficiencies of up to 15.3%. Notably, triplet-triplet annihilation has been significantly reduced, as exemplified by a very small efficiency roll-off of ∼1% at a practical brightness of 500 cd m^-2.

Tri- and tetraarylanthracenes with novel λ, χ and ψ topologies as blue-emissive and fluorescent host materials in organic light-emitting diodes (OLEDs)

Aryl-anthracene derivatives with λ, χ and ψ topologies serve as materials in OLEDs with intriguingly similar physical and electroluminescence properties.

Copper-mediated phospha-annulation to attain water-soluble polycyclic luminophores

The P-heterocyclic fluorophores, obtained via Cu(ii)-mediated cyclization, are suitable for cell imaging due to their stability, water solubility and low toxicity.

Computational design of high efficiency nonplanar tri-s-triazine-based ambipolar host materials for phosphorescent blue emitters

A series of nonplanar tri-s-triazine-based molecules were designed, and their optical, electronic, and charge transport properties as ambipolar host materials for blue electrophosphorescence emitters were explored by density functional theory. The influence of the linkage between tri-s-triazine and carbazole, diphenylamine and triphenylamine, as well as the influence of a series of electron-donating and electron-withdrawing substituents on triplet energy, energy level matching and charge transport of the designed molecules was discussed in detail. Our results reveal that the molecules under investigation can serve as host materials for blue electrophosphorescence emitters. We also predicted the mobility of designed molecules with better performance in the P1[combining macron] space group. Based on the investigated results, we proposed a rational way for the design of host materials for OLEDs, and also expanded the application field of tri-s-triazine.

Ambipolar Phosphine Derivatives to Attain True Blue OLEDs with 6.5% EQE

A family of new branched phosphine derivatives {Ph2N-(C6H4)n-}3P → E (E = O 1-3, n = 1-3; E = S 4-6, n = 1-3; E = Se 7-9, n = 1-3; E = AuC6F5 4-6, n = 1-3), which are the donor-acceptor type molecules, exhibit efficient deep blue room temperature fluorescence (λem = 403-483 nm in CH2Cl2 solution, λem = 400-469 nm in the solid state). Fine tuning the emission characteristics can be achieved varying the length of aromatic oligophenylene bridge -(C6H4)n-. The pyramidal geometry of central R3P → E fragment on the one hand disrupts π-conjugation between the branches to preserve blue luminescence and high triplet energy, while on the other hand provides amorphous materials to prevent excimer formation and fluorescence self-quenching. Hence, compounds 2, 3, 5, and 12 were used as emitters to fabricate nondoped and doped electroluminescent devices. The luminophore 2 (E = O, n = 2) demonstrates excellently balanced bipolar charge transport and good nondoped device performance with a maximum external quantum efficiency (EQEmax) of 3.3% at 250 cd/m(2) and Commission International de L'Eclairage (CIE) coordinates of (0.15, 0.08). The doped device of 3 (E = O, n = 3) shows higher efficiency (EQEmax of 6.5, 6.0 at 100 cd/m(2)) and high color purity with CIE (0.15, 0.06) that matches the HDTV standard blue. The time-resolved electroluminescence measurement indicates that high efficiency of the device can be attributed to the triplet-triplet annihilation to enhance generation of singlet excitons.

Functionalization of phosphorescent emitters and their host materials by main-group elements for phosphorescent organic light-emitting devices

Phosphorescent organic light-emitting devices (OLEDs) have attracted increased attention from both academic and industrial communities due to their potential practical application in high-resolution full-color displays and energy-saving solid-state lightings. The performance of phosphorescent OLEDs is mainly limited by the phosphorescent transition metal complexes (such as iridium(III), platinum(II), gold(III), ruthenium(II), copper(I) and osmium(II) complexes, etc.) which can play a crucial role in furnishing efficient energy transfer, balanced charge injection/transporting character and high quantum efficiency in the devices. It has been shown that functionalized main-group element (such as boron, silicon, nitrogen, phosphorus, oxygen, sulfur and fluorine, etc.) moieties can be incorporated into phosphorescent emitters and their host materials to tune their triplet energies, frontier molecular orbital energies, charge injection/transporting behavior, photophysical properties and thermal stability and hence bring about highly efficient phosphorescent OLEDs. So, in this review, the recent advances in the phosphorescent emitters and their host materials functionalized with various main-group moieties will be introduced from the point of view of their structure-property relationship. The main emphasis lies on the important role played by the main-group element groups in addressing the key issues of both phosphorescent emitters and their host materials to fulfill high-performance phosphorescent OLEDs.

High performance full color OLEDs based on a class of molecules with dual carrier transport channels and small singlet-triplet splitting

Two deep blue emitting materials PPI-PPITPA and PPI-PPIPCz with dual carrier transport properties and small singlet-triplet splitting features are designed and synthesized. PPI-PPITPA and PPI-PPIPCz were used not only as non-doped emitting layers to fabricate highly efficient deep blue OLEDs, but also as hosts to construct high performance green, yellow and red phosphorescent OLEDs.

Bis(phosphine oxide)/triphenylamine based material for solution-processed blue electrofluorescent and green electrophosphorescent devices

A novel multifunctional material TPA-BPhPO has been designed and synthesized to explore its use as the blue emitter and the host material for solution-processed blue electrofluorescent and green electrophosphorescent devices.

Twisted biaryl-amines as novel host materials for green-emissive phosphorescent organic light-emitting diodes (PhOLEDs)

Insertion of rigid biaryl moieties between two phenyl rings of CBP leads to host materials with improved thermal stabilities (T_gs ∼111–148 °C) and high triplet energies (2.63–2.83 eV) to permit their application as host materials for green phosphor, i.e., Ir(ppy)₃.

Molecular design of triazine and carbazole based host materials for blue phosphorescent organic emitting diodes

The triplet energy of the host was managed by inserting a methyl substituent in the phenyl linkage between triazine and carbazole.

New bipolar host materials for high performance of phosphorescent green organic light-emitting diodes

New bipolar host materials with indenocarbazole and biphenyl pyrimidine moieties are successfully designed and synthesized. The host materials demonstrate excellent electro-optical properties and OLED device performances.

Synthesis of triphenylamine based polysiloxane as a blue phosphorescent host

Triphenylamine based polysiloxane has been successfully synthesized as a phosphorescent host. This work demonstrates that modifying triphenylamine by polysiloxane is a promising approach to improve its physical properties while maintaining its electronic properties.