A Light-Blue Phosphorescent Dendrimer for Efficient Solution-Processed Light-Emitting Diodes

Lo, Shih‐Chun; Richards, Gary J.; Markham, Jonathan P. J.; Namdas, Ebinazar B.; Sharma, Sanjay; Burn, Paul L.; Samuel, Ifor D. W.

doi:10.1002/adfm.200400560

Cited by 138 publications

(78 citation statements)

References 35 publications

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“…5) phosphorescent dendrimers, giving DLEDs with excellent efficiencies. There are two interesting points to note about the red [49,50] and sky-blue [51] emissive dendrimers. For the red-emissive dendrimers two types of iridium(III) complexes were explored: one in which all three ligands were the same (a homoleptic complex) and the other in which two ligands were different from the third (a heteroleptic complex).…”

Section: Developing Other Colorsmentioning

confidence: 98%

The Development of Light‐Emitting Dendrimers for Displays

Burn¹,

Lo²,

Samuel³

2007

Advanced Materials

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466

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Dendrimers are now an important class of light‐emitting material for use in organic light‐emitting diodes (OLEDs). Dendrimers are branched macromolecules that consist of a core, one or more dendrons, and surface groups. The different parts of the macromolecule can be selected to give the desired optoelectronic and processing properties. The first light‐emitting dendrimers were fluorescent but more recently highly efficient phosphorescent dendrimers have been developed. OLEDs containing light‐emitting dendrimers have been reported to have external quantum efficiencies of up to 16 %. The solubility of the dendrimers opens the way for simple processing and a new class of flat‐panel displays. In this Review we show how the structure of the light‐emitting dendrimers controls key features such as intermolecular interactions and charge transport, which are important for all OLED materials. The advantages of the dendrimer architecture for phosphorescent emitters and the way the structure can be varied to enhance materials performance and device design are illustrated.

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Section: Developing Other Colorsmentioning

confidence: 98%

The Development of Light‐Emitting Dendrimers for Displays

Burn¹,

Lo²,

Samuel³

2007

Advanced Materials

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466

252

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“…1 H, 13 C, and 19 F NMR confirmed the formation of a polymer with significant peak broadening occurring with respect to the monomer 11. GPC anlysis gave the molecular weight The final part of this study was to determine the effect of the polymerization on the photophysical properties of the emissive dendrimer.…”

Section: Resultsmentioning

confidence: 82%

“…Nitroxide initiatior (12) was added (1 mol%) and the polymerisation was allowed to proceed at 130 °C for 72 hours. A green emissive material was isolated and the NMR spectra ( 1 H, 13 C, and 19 F) were found to all have broader peaks than the monomer indicating that a higher molecular weight material had been formed. Gel permeation chromatography (GPC) analysis against polystyrene standards gave the weight average molecular weight ) ( W M as 8000 and a polydispersity of 1.8.…”

Section: Resultsmentioning

confidence: 99%

“…The organic layer was washed with water (2 × 50 mL), dried over sodium sulfate, filtered and the solvent removed in vacuo. This crude material was purified by flash column chromatography over silica using light petroleum:diethyl ether (1:0 → 0:1) mixtures as eluent to give 10 (592 mg, 72%), which had identical 1 H and 13 C NMR spectra to the literature 28 .…”

Section: Methodsmentioning

confidence: 99%

“…For example, phosphorescent dendrimers with different iridium(III) complex cores [(1), (2), and (3) (Fig. 1) give red 11 , green 12 , and sky blue 13 emission respectively], biphenyl-based dendrons, and 2-ethylhexyloxy surface groups have all given rise to efficient OLEDs [14][15][16] . However, thus far all the reported dendrimer devices have been fabricated by spin-coating from solution leading to monochrome displays.…”

Section: Introductionmentioning

confidence: 99%

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Light-emitting poly(dendrimer)s

et al. 2008

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Organic light-emitting diodes (OLEDs) have great potential for displays and lighting applications. For large area displays the ideal materials would be both phosphorescent and solution processible. These requirements mean that the materials need to be able to be patterned and the most advanced method for forming pixelated displays is inkjet printing. Light-emitting phosphorescent dendrimers have given high efficiency monochrome displays with the emitting layer deposited by spin-coating. However, the viscosity of the dendrimer solutions is insufficient for inkjet printing. We report the development of a new class of light-emitting materials, namely poly(dendrimers) in which a green emissive phosphorescent dendrimer is attached to a poly(styrene) backbone. Free radical polymerization of a dendrimer-styrene monomer gave a poly(dendrimer) with a weight average molecular weight of 24000 and a polydispersity of 3.6. A dilute solution of the dendrimer had a viscosity 15% higher than the neat solvent. Comparison of the photophysical studies of the poly(dendrimer) versus a model monomer dendrimer showed that the PL spectrum was broader and red-shifted, and the PL quantum yield around 50% lower. This was attributed to intermolecular interactions of the emissive dendrimers, which are held closely together on the polymer backbone.

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Dendrimers

Svenson¹

2006

Kirk-Othmer Encyclopedia of Chemical Technology

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Dendritic polymers (dendrimers) are synthesized in a layer‐by‐layer fashion around a core molecule. Depending on the number of chemical functionalities and the shape of the core, dendrimers of various shapes and complexities can be produced with very low polydispersity. The high level of control over the architecture of dendrimers, their size, shape, branching length and density, and their surface functionality, makes these compounds ideal materials in medical and technical applications, such as drug delivery, gene transfection, imaging, luminescence, quantum dot stabilization, catalysis and waste remediation. The active agents may either be encapsulated into the interior of the dendrimers or they can be chemically attached or physically adsorbed onto the dendrimer surface, with the option to tailor the properties of the dendritic carrier to the specific needs of the active material in its specific applications. Surface modified dendrimers themselves may act as nanodrugs against tumors, bacteria, and viruses. Recent successes in simplifying the synthesis of dendrimers, such as the “lego” and “click” approaches, have provided a vastly expanded variety of dendritic compounds, while at the same time reducing the cost of their production.

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A Light-Blue Phosphorescent Dendrimer for Efficient Solution-Processed Light-Emitting Diodes

Cited by 138 publications

References 35 publications

The Development of Light‐Emitting Dendrimers for Displays

The Development of Light‐Emitting Dendrimers for Displays

Light-emitting poly(dendrimer)s

Dendrimers

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