Maximizing&lt;tex&gt;$hbox Alq_3$&lt;/tex&gt;OLED Internal and External Efficiencies: Charge Balanced Device Structure and Color Conversion Outcoupling Lenses

Li, Weixin; Jones, Robert A.; Allen, Steven C.; Heikenfeld, Jason; Steckl, A. J.

doi:10.1109/jdt.2006.874507

Cited by 61 publications

(31 citation statements)

References 43 publications

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“…The efficiency of this device shows an only a moderate drop in the observed current density window up to 180 mA/cm², for the technically important brightness of 100 cd/m 2 , an efficiency above 2 cd/A was detected. These findings are rather promising also in comparison with similar Alq 3 -based bilayer devices [1,27] as well as to PVK-based devices. [28] It should be pointed out that these OLED characteristics were obtained in non-optimized test devices under ordinary laboratory conditions.…”

Section: Resultssupporting

confidence: 57%

Polyethers containing 3,6-diarylcarbazolyl groups as polymeric materials for hole transporting layers of OLEDs

Kručaitė

Liu

Volyniuk

et al. 2015

Designed Monomers and Polymers

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Several polyethers containing pendent 3,6-diarylcarbazolyl moieties have been synthesized by the multi-step synthetic routes. Full characterization of their structures is presented. The polymers represent materials of high thermal stability with initial thermal degradation temperatures exceeding 419°C. The glass transition temperatures of the amorphous materials were in the range of 66-108°C. The electron photoemission spectra of thin layers of the polymers showed ionization potentials in the range of 5.47-5.69 eV. Hole transporting properties of the polymeric materials were tested in the structures of organic light emitting diodes with Alq 3 as the green emitter. The device containing hole transporting layers of the polymer with 3,6-di(4-biphenyl)carbazolyl moieties exhibited the best overall performance with a maximum photometric efficiency of about 2.3 cd/A and maximum brightness exceeding 2630 cd/m 2 .

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Section: Resultssupporting

confidence: 57%

Polyethers containing 3,6-diarylcarbazolyl groups as polymeric materials for hole transporting layers of OLEDs

Kručaitė

Liu

Volyniuk

et al. 2015

Designed Monomers and Polymers

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“…Moreover, the HFI provides an important spin mixing mechanism for polaron-pairs in Alq 3 In contrast, the MC(B) response is much less sensitive to isotope exchange and thus the HFI-based spin mixing mechanism here is overwhelmed by another, isotope insensitive spin mixing mechanism. To explain the low field behavior of MC in Alq 3 we offer an isotope independent interaction between free carrier with S=½ and triplet-state PP. …”

Section: Discussionmentioning

confidence: 95%

“…The competing models include: (i) spin mixing in oppositely charged polaron-pairs (PP) and in pairs of samecharge polarons (or bipolarons, BP) by the hyperfine interaction (HFI) 4,6,11,12 ; (ii) spin mixing within triplet-triplet annihilation (TTA) process 7 ; and (iii) spin mixing during the process of triplet exciton quenching by spin ½ charge polarons 8 . Importantly, the HFI proposed models should differ substantially from the other models in the response to isotope exchange in the Alq 3 molecule active layer, where all hydrogen atoms (nuclear spin I H =½, nuclear g-factor g H =5.586) are exchanged by deuterium atoms (I D =1, g D /g H =0.154). This should occur since the HFI constant, a HF , scales with the nuclear g-factor 13 , whereas the other proposed interactions are mostly isotope insensitive.…”

Section: Introductionmentioning

confidence: 95%

“…1(a) inset] is a common active molecular layer used in organic light emitting devices (OLED), due to its efficient electro-luminescence (EL) emission and high electron mobility [1][2][3] . It is thus not surprising that magnetic field effects (MFE) in Alq 3 -based OLED devices such as magnetoelectroluminescence (MEL) and magneto-conductance (MC) have been extensively studied in the last few years [4][5][6][7][8][9][10] .…”

Section: Introductionmentioning

confidence: 99%

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Isotope effect in the spin response of aluminum tris(8-hydroxyquinoline) based devices

Nguyen

Basel

et al. 2012

Phys. Rev. B

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We studied the spin response of various magnetic field effects and magneto-transport in both protonated and deuterated aluminum tris(8-hydroxyquinoline) [Alq 3 ]-based organic light emitting diodes and spin-valve devices. Both conductivity-detected magnetic resonance in diodes and magneto-resistance in spin valves show substantial isotope dependence pointing to the importance of the hyperfine interaction (HFI) in the spin response of spin ½ charge polarons in Alq 3 . In addition the low field (B<20 mT) magneto-electroluminescence (MEL) response is also isotope sensitive, showing that HFI-induced spin mixing of polaron-pairs spin sublevels dominates this response too. However, the magneto-conductance (MC) response was found to be much less sensitive to isotope exchange at low fields, in agreement with previous studies. The disparity between the isotope sensitivity of MC and MEL responses in Alq 3 indicates that the HFI in the MC response is overwhelmed by an isotope independent spin mixing mechanism. We propose that collisions of spin ½ carriers -with triplet species such as polaron pairs may be the main spin mixing mechanism in the low field MC response in Alq 3 diodes.

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“…The situation with hemispherical scatterers partially also resembles efforts to improve OLED outcoupling efficiency by micro lens arrays on top of the OLED structure at the outcoupling side (see, e.g., [45]). But those micro lenses rather have typical sizes in the many microns or even millimeter range.…”

Section: Numerical Calculationsmentioning

confidence: 99%

nm- andμm-Scale Surface Roughness on Glass with Specific Optical Scattering Characteristics on Demand

Fouckhardt

Steingoetter

Brinkmann

et al. 2007

Advances in OptoElectronics

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During maskless ion etching of amorphous glass, self-organization can arise in certain etch parameter ranges, which leads to dense-lying dots/cones with typical diameters and heights in the 30-300 nm range. Another phenomenon, which results in cone sizes around 1 μm or more, is self-masking especially in the case of heterogeneous glasses like borosilicate glass as used in this contribution. Thus, a wide range of characteristic sizes and shapes of individual scatterers on the glass surface, jointly acting as a defined roughness, can be achieved resulting in specific optical scattering characteristics. This contribution gives results on borosilicate thin-glass dry etching. Certain surface morphologies are reported together with experimental results on their optical scattering characteristics.

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Maximizing<tex>$hbox Alq_3$</tex>OLED Internal and External Efficiencies: Charge Balanced Device Structure and Color Conversion Outcoupling Lenses

Cited by 61 publications

References 43 publications

Polyethers containing 3,6-diarylcarbazolyl groups as polymeric materials for hole transporting layers of OLEDs

Polyethers containing 3,6-diarylcarbazolyl groups as polymeric materials for hole transporting layers of OLEDs

Isotope effect in the spin response of aluminum tris(8-hydroxyquinoline) based devices

nm- andμm-Scale Surface Roughness on Glass with Specific Optical Scattering Characteristics on Demand

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