Materials and Devices toward Fully Solution Processable Organic Light-Emitting Diodes

Zhong, Chengmei; Duan, Chunhui; Huang, Fei; Wu, Hongbin; Cao, Yong

doi:10.1021/cm101937p

Cited by 416 publications

(259 citation statements)

References 143 publications

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“…The advantages of solution processing over thermal evaporation have been widely recognized. 16,17,18,19,20 To address these issues we have explored systematic functionalization of the ppy ligands of is straightforward to synthesise and has been obtained in >1 g batches. mmol) in 1,2-dimethoxyethane (20 mL) was degassed by bubbling argon through the mixture for 15 min.…”

Section: Introductionmentioning

confidence: 99%

Cyclometalated Ir(III) Complexes for High-Efficiency Solution-Processable Blue PhOLEDs

et al. 2013

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Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThis article reports the systematic functionalization of FIrpic (1)

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Section: Introductionmentioning

confidence: 99%

Cyclometalated Ir(III) Complexes for High-Efficiency Solution-Processable Blue PhOLEDs

et al. 2013

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“…A new generation of WMLs fi rst introduced by Cao et al is based on polyelectrolytes or tertiary aliphatic amines, such as poly [(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt -2,7-(9,9-dioctylfluorene)] (PFN) and the corresponding ethyl ammonium bromide. [ 1 ] Although these materials improve carrier injection or extraction in different organic diode devices, [1][2][3][4][5][6][7] the mechanism behind this improvement is not completely clear. This ambiguity hinders design, selection and optimization of new WMLs.…”

mentioning

confidence: 99%

Origin of Work Function Modification by Ionic and Amine‐Based Interface Layers

Reenen

Kouijzer

Janssen

et al. 2014

Adv Materials Inter

131

138

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can evolve into a successful thin fi lm photovoltaic technology. To this end, further improvements in the sunlight-toelectricity conversion effi ciency are still needed. To do so, not only the optoelectronic, active layer should be considered, but also the connection between this layer and the electrodes. This connection is facilitated by so-called work function modifi cation layers (WMLs) that serve to align the transport levels in the organic semiconductor and the conductor by modifi cation of the work function. Materials that are often used are poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) for improving hole collection and injection in combination with an indium tin oxide (ITO) electrode and LiF for the electron contact in combination with an Al metal electrode. A new generation of WMLs fi rst introduced by Cao et al. is based on polyelectrolytes or tertiary aliphatic amines, such as poly [(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt -2,7-(9,9-dioctylfluorene)] (PFN) and the corresponding ethyl ammonium bromide. [ 1 ] Although these materials improve carrier injection or extraction in different organic diode devices, [1][2][3][4][5][6][7] the mechanism behind this improvement is not completely clear. This ambiguity hinders design, selection and optimization of new WMLs.Mechanisms that are generally considered to result in electric fi elds and concomitant work function shifts at metal-organic interfaces are doping, charge transfer, and dipole formation. [8][9][10] Regarding the work function modifi cation of amine side-groups, Lindell et al. [ 11 ] found by photoelectron spectroscopy and density functional calculations that the electron donor para-phenylenediamine chemisorbs onto atomically clean Ni in vacuum. [ 12 ] Due to partial electron transfer from the amine unit, a work function reduction of 1.55 eV is achieved, resulting in a less deep Fermi level. This explanation is not likely to hold for the technologically more relevant procedure on which we shall focus, being the deposition of WMLs from solution on a metal at atmospheric pressure: the metal is not atomically clean, which likely inhibits chemisorption. In other work by Zhou et al. [ 13 ] it is shown that the work function reduction, at atmospheric pressure, by the amine groups in poly(ethylenimine ethoxylated) (PEIE), is generally the same on different conductors. Work function modifi cation by polyelectrolytes and tertiary aliphatic amines is found to be due to the formation of a net dipole at the electrode interface, induced by interaction with its own image dipole in the electrode. In polyelectrolytes differences in size and side groups between the moving ions lead to differences in approach distance towards the surface. These differences determine magnitude and direction of the resulting dipole. In tertiary aliphatic amines the lone pairs of electrons are anticipated to shift towards their image when close to the interface rather than the nitrogen nuclei, which are sterically hindered by the alkyl side chains. ...

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“…Organic light sources are currently made from either low molecular weight organic materials or polymers. For the former, the layer structure of the OLED is usually deposited on a rigid base made from glass or metal [31][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

Optical Properties and Quantum-Chemical Calculations of Various Bithienyl Derivatives of Benzene, Triazine and Triphenyltriazine as Organic Light Emitting Diodes

Idzik¹,

Cywiński²,

Kuźnik³

et al. 2017

J Chem Eng Process Technol

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Derivatives of tris (2,2-bithiophen-5-yl) derivatives based on a benzene, a triazine or a triphenyltriazine core are presented for optical light emitting diode functionality. Optical properties as well as their corresponding molecular energy levels were investigated by UV-VIS absorption supported by fluorescence spectra. Furthermore, DFT and TDDFT calculations for obtained materials are presented to supplement the experimental data. It is demonstrated that HOMO -LUMO orbitals are delocalized uniformly on aromatic core and bithienyl substituents. Additionally, an OLED was built using synthesized compounds to facilitate electron transport and act as light emitting layer. Optical and charge transport properties along with good electrochemical stability confirm potential application of bithiophenearomatic hybrids in electrochromic devices, light emitting electrochemical cells and spintronics.

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Materials and Devices toward Fully Solution Processable Organic Light-Emitting Diodes

Cited by 416 publications

References 143 publications

Cyclometalated Ir(III) Complexes for High-Efficiency Solution-Processable Blue PhOLEDs

Cyclometalated Ir(III) Complexes for High-Efficiency Solution-Processable Blue PhOLEDs

Origin of Work Function Modification by Ionic and Amine‐Based Interface Layers

Optical Properties and Quantum-Chemical Calculations of Various Bithienyl Derivatives of Benzene, Triazine and Triphenyltriazine as Organic Light Emitting Diodes

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