Efficient single-layer “twistacene”-doped polymer white light-emitting diodes

Xu, Qihong; Duong, Hieu M.; Wudl, Fred; Yang, Yang

doi:10.1063/1.1808250

Cited by 143 publications

(105 citation statements)

References 19 publications

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“…[1][2][3] White light-emitting diodes (WLEDs) have been achieved using dye/polymer 4 or polymer/polymer blends 5 as the active medium. However, phase separation, difficulties in controlling the doping level, or undesired energy transfer between chromophores have been problems with these WLEDs.…”

Section: Introductionmentioning

confidence: 99%

White-light-emitting diode based on a single-layer polymer

2013

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A broad-band light-emitting diode was achieved in a single-layer device based on pure poly(9,9′-dioctylfluorene-co-bis-N,N′-(4-butylphenyl)-bis-N,N′-phenyl-1,4-phenylenediamine) (PFB). Electromer emission was observed in the red with a center wavelength of about 620 nm in electroluminescence (EL) spectrum. This kind of emission exhibits strong dependence on the thickness of the PFB layer, so that the shape of the EL spectrum may be adjusted through changing the thickness of the active polymer layer to balance between the intrinsic PFB emission in the blue and the electromer emission in the red. Thus, white light emission may be achieved from such a single-layer single-material diode.

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Section: Introductionmentioning

confidence: 99%

White-light-emitting diode based on a single-layer polymer

2013

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“…10 Recently, some of us have reported a successful strategy to twist the otherwise planar structure of HATNA by introducing bulky silyl groups in confronting positions and to influence their properties by means of such distortions. 11 Distorted polycyclic aromatic hydrocarbons [12][13][14][15][16][17] have emerged as promising materials for OLED applications [18][19][20][21][22] since the twisted conformation substantially reduces intermolecular p-p interactions, leading to enhanced solubility and to a reduction of aggregation-induced quenching in the solid state.…”

mentioning

confidence: 99%

Virtually pure near-infrared electroluminescence from exciplexes at polyfluorene/hexaazatrinaphthylene interfaces

Tregnago

Fléchon

Choudhary

et al. 2014

Applied Physics Letters

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Electronic processes at the heterojunction between chemically different organic semiconductors are of special significance for devices such as light-emitting diodes (LEDs) and photovoltaic diodes. Here, we report the formation of an exciplex state at the heterojunction of an electron-transporting material, a functionalized hexaazatrinaphthylene, and a hole-transporting material, poly(9,9-dioctylfluorene-alt-N-(4-butylphenyl)diphenylamine) (TFB). The energetics of the exciplex state leads to a spectral shift of ∼1 eV between the exciton and the exciplex peak energies (at 2.58 eV and 1.58 eV, respectively). LEDs incorporating such bulk heterojunctions display complete quenching of the exciton luminescence, and a nearly pure near-infrared electroluminescence arising from the exciplex (at ∼1.52 eV) with >98% of the emission at wavelengths above 700 nm at any operational voltage.

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“…There exist, though, examples when polyaromatic hydrocarbons are used as yellow--orange emitting dopants dispersed in blue emitters (single layer--two components) 50 or mixed with thermally delayed fluorescent emitters. 51 In the first case the devices had impressive luminance but their current and power efficiencies where slightly lower than those of 3 OLEDs.…”

Section: Please Do Not Adjust Marginsmentioning

confidence: 99%

Nine-ring angular fused biscarbazoloanthracene displaying a solid state based excimer emission suitable for OLED application

et al. 2016

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A new biscarbazoloanthracene consisting of nine fused aromatic rings, including two pyrrole units, has been obtained in a straightforward and convergent synthesis. Computational chemistry and conformational analysis revealed that the semiconductor's molecule is not planar, the two carbazole moieties being helical twisted from the plane of the anthracene unit. Photophysical and electrochemical measurements showed that this angular fused heteroacene has a low lying HOMO energy level with a wide band gap despite its extended π--conjugated molecular framework. Based on its relatively low--lying HOMO level, the titled compound semiconductor promises a high environmental stability in comparison to other related linear fused acenes and heteroacenes. The biscarbazoloanthracene has been applied as the light emitting layer in a white light emitting diode (WOLED). It is proposed that the white OLED feature is due to dual light emission properties from the active semiconductor layer being based on both the molecular luminescence of the small molecule and a discrete excimer emission made possible by suitable aggregates in the solid state. Noteworthy, this is the first reported example of such a behavior observed in a small molecule heteroacene rather than an oligomer or a polymer.

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Efficient single-layer “twistacene”-doped polymer white light-emitting diodes

Cited by 143 publications

References 19 publications

White-light-emitting diode based on a single-layer polymer

White-light-emitting diode based on a single-layer polymer

Virtually pure near-infrared electroluminescence from exciplexes at polyfluorene/hexaazatrinaphthylene interfaces

Nine-ring angular fused biscarbazoloanthracene displaying a solid state based excimer emission suitable for OLED application

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