Heck coupling of haloaromatics with octavinylsilsesquioxane: solution processable nanocomposites for application in electroluminescent devices

Sellinger, Alan; Tamaki, Ryo; Laine, Richard M.; Ueno, Kazunori; Tanabe, Hiroshi; Williams, Evan L.; Jabbour, Ghassan E.

doi:10.1039/b505048k

Cited by 96 publications

(93 citation statements)

References 19 publications

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“…Kleverlaan and Feilzer (2005) [14] showed that dimethacrylate composites have percentage shrinkages of 2-4% and stress values of 12-17 MPa, whereas other authors reported stress values of 6-9 MPa, and 8-12.5 MPa [26]. Thus, the material rigidity has a strong influence on the final polymerization tension [27]. As the rigidity is more associated with the crosslink density of the polymeric network than with the full conversion of the reactive species, the elastic modulus may be increased without much effect on the DC [2].…”

Section: Discussionmentioning

confidence: 81%

Evaluation of the flexural resistance and stress contraction of a silorane-based composite submitted to different protocols of polymerization

Lopes¹,

Serralvo²,

Felizardo

et al. 2014

Appl Adhes Sci

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When introduced to the market, silorane-based materials promised less contraction compared to other materials. The purpose of this study was to evaluate the contraction stress, flexural strength, and elastic modulus of the Filtek Silorane composite with different photoactivation protocols. Filtek Silorane and Filtek Z350 composites were inserted in a circular photoelastic resin matrix and subjected to photoactivation at 650 mW cm 2 for 40 s (protocol I), 325 mW cm 2 for 80 s (protocol II), 100 mW cm 2 for 260 s (protocol III), 100 mW cm 2 for 5 s + 1 min delay +650 mW cm 2 for 39.5 s (protocol IV), or 100 mW cm 2 for 5 s + 3 min delay +650 mW cm 2 for 39.5 s (protocol V). Five samples were prepared for each resin with each photoactivation protocol. To determine contraction stress, fringes were analyzed in a polariscope. For flexural strength analyses, 25 specimens (10 × 2 × 2 mm) of each resin with each photoactivation protocol were submitted to the 3-point bending test in a universal testing machine. Data were submitted to ANOVA and post hoc Tukey's tests (α = 0.05). Filtek Silorane showed higher contraction stress results than Filtek Z350 for protocols II (16.4 ± 3.88 vs. 5.9 ± 1.64 MPa), IV (17 ± 2.67 vs. 8.8 ± 1.30 MPa), and V (16.3 ± 3.33 vs. 5.1 ± 1.95 MPa). Both resins showed similar flexural strength values, but the elastic modulus of Filtek Silorane was significantly higher with all photoactivation protocols. Pulse-delay photoactivation was effective for Filtek Z350, but not Filtek Silorane, because the elastic modulus and contraction stress were reduced for Filtek Z350 without any change in flexural strength.

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Section: Discussionmentioning

confidence: 81%

Evaluation of the flexural resistance and stress contraction of a silorane-based composite submitted to different protocols of polymerization

Lopes¹,

Serralvo²,

Felizardo

et al. 2014

Appl Adhes Sci

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“…Especially, performing the multiple transformations generally results in fairly low yield and remarkably difficult purification. [40,41] Constructing these complex dendritic materials conveniently with high yield and purity is thus greatly challenging.…”

Section: Star-shaped Polyfluorenesmentioning

confidence: 99%

Polyfluorene‐Based Blue‐Emitting Materials

Zhao

Liu

Huang

2009

Macro Chemistry & Physics

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Polyfluorenes are a class of promising blue light‐emitting conjugated polymer due to their excellent optoelectronic properties. However, the applications of polyfluorenes in polymer light‐emitting diodes (PLEDs) have been hampered by the appearance of long‐wavelength green emission, leading to the problem of color purity and stability. Hence, the preparation of pure blue‐emitting polyfluorenes becomes very important for the realization of real blue‐emitting PLEDs. In this short review, we introduce the efforts made by our group to realize polyfluorenes with pure blue emission, including the incorporation of spirobifluorene units, heterofluorene units, hyperbranched, and star‐shaped structures into polymer backbones.

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“…21 Fourth, the functional groups are projecting in 3 dimensions thus producing a rigid spherical core from which to attach the dendrons of interest. These rigid spheres have been shown to promote amorphous properties that are known to be important for OLED devices.In continuation of our research on solution processable hybrid materials, [22][23][24] we report here the preparation of phosphorescent based CP materials for use as emissive layers in OLEDs. Our goal is to develop a platform from which many different solution processable phosphorescent materials can be prepared with optimal thermal, electronic and optical properties well suited for OLEDs.…”

mentioning

confidence: 99%

Solution processable phosphorescent dendrimers based on cyclic phosphazenes for use in organic light emitting diodes (OLEDs)

et al. 2008

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A novel solution processable phosphorescent dendrimer based on cyclic phosphazene (CP) cores has been prepared and used as emissive layers in simple OLED architectures, providing efficiencies of 24.0 cd A 21 and 16.7 lm W 21 .Organic and polymeric light emitting diode (OLED) technology has progressed immensely since the initial reports by Tang 1 and Friend 2 in 1987 and 1990 respectively. From these earliest discoveries through the late 1990's, almost all OLED reports were based on fluorescent emissive materials. As a result, champion OLED efficiencies were limited to around 10 lm W 21 which made their application in display technology promising but no chance for solid-state lighting that requires efficiencies of .30 lm W 21 . With the discovery of platinum and iridium based phosphorescent complexes, 3,4 OLED efficiencies .30 lm W 21 have been achieved and thus application in both display and lighting applications have become even more promising. 5 For these active materials, both small molecules and polymers are currently the preferred candidates. Small-molecules are advantageous as they can be highly purified and vacuum deposited in multi-layer stacks, both important for device lifetime and efficiency. However, vacuum deposition techniques generally require expensive equipment, a limitation to display size, and complicated full color display production processes at high volume using masking technologies. 6 Polymers are generally of lower purity than small molecules but can access larger display sizes at much lower costs using solution-based deposition techniques such as spray coating, ink jet and screen printing. 7,8 Having a set of materials with properties intermediate between small molecules and polymers would be very advantageous. One such family of materials are dendrimers that have molecular weights in the favorable range between 1000-10 000 g mol 21 . Favorable because dendrimers can be purified to a high degree using chromatographic techniques, are soluble in common solvents, and allow synthetic versatility for tuning charge transport 9-12 and emissive [13][14][15][16] properties. Finally dendrimers of different emission colors can be physically blended together without phase separation for possible application in white lighting.Cyclic phosphazenes (CP), with a planar non-delocalized cyclic ring consisting of alternating N and P atoms, are an interesting class of materials that offers access to dendrimeric materials. The inorganic phosphazenes have been well studied in both the cyclic and linear forms by several groups due to their diverse properties including excellent hydrolytic stability, thermal stability, flame retardant properties, and liquid crystalline behaviour to name a few. [17][18][19][20] The CP core provides many advantageous properties towards useful materials for solution processable OLEDs. First, the chemistry to prepare functionalized CP cores is very straightforward. Second, the functionalized CP cores are very stable and do not breakdown even under very aggressive chemical condition...

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Heck coupling of haloaromatics with octavinylsilsesquioxane: solution processable nanocomposites for application in electroluminescent devices

Cited by 96 publications

References 19 publications

Evaluation of the flexural resistance and stress contraction of a silorane-based composite submitted to different protocols of polymerization

Evaluation of the flexural resistance and stress contraction of a silorane-based composite submitted to different protocols of polymerization

Polyfluorene‐Based Blue‐Emitting Materials

Solution processable phosphorescent dendrimers based on cyclic phosphazenes for use in organic light emitting diodes (OLEDs)

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