Influence of extrinsic and intrinsic parameters onto the formation of surface relief gratings in polar azo molecular glasses

Jacquart, Aurélie; Morin, Edouard; Yang, Feng; Geffroy, Bernard; Ishow, Eléna

doi:10.1016/j.dyepig.2011.04.001

Cited by 9 publications

(12 citation statements)

References 32 publications

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“…15,16 To this end, azobenzene derivatives capable of forming glassy phases have been synthesized by various groups, and it was demonstrated that such materials show photomechanical properties similar to those of their polymer counterparts. [21][22][23][24][25][26] On the other hand, current azobenzene-based molecular glasses based on triarylamines suffer from certain limitations. Firstly, their synthesis requires multiple steps and typically give modest overall yields, thereby limiting their commercial potential.…”

Section: Introductionmentioning

confidence: 99%

Disperse and disordered: a mexylaminotriazine-substituted azobenzene derivative with superior glass and surface relief grating formation

et al. 2014

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Section: Introductionmentioning

confidence: 99%

Disperse and disordered: a mexylaminotriazine-substituted azobenzene derivative with superior glass and surface relief grating formation

et al. 2014

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“…Almost 20 years ago, Natansohn et al 1 and Kumar et al 2 reported independently one of the most exciting behaviours of azo-polymers: the capacity to generate surfaces with sinusoidal topography as a consequence of light irradiation through an interference pattern. Surface relief gratings (SRGs) are the result of the trans-cis isomerisation of the azobenzene groups, either linked to a polymeric chain [1][2][3][4][5][6][7] or as part of azo dye doped polymers (guest-host systems). 8 Despite the large number of studies attempting to characterize this process, the mechanism underlying the SRG formation is still unclear.…”

Section: Introductionmentioning

confidence: 99%

Direct observation of athermal photofluidisation in azo-polymer films

et al. 2014

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The surface relief gratings (SRGs) can be generated when azo-polymer films are exposed to laser beam interference as a result of mass migration. Despite considerable research effort over the past two decades this complex phenomenon remains incompletely understood. Here we show, for the first time, the athermal photofluidisation of azo-polysiloxane films exposed to 488 nm light, directly monitored by optical microscopy. A process of surface relief erasure occurring in parallel with its inscription was also observed during laser irradiation. We therefore propose a new mechanism of SRG formation, based on three different processes: (1) the polymer photo-fluidization in illuminated regions, (2) the mass displacement from illuminated to dark regions and (3) the inverse mass displacement, from dark to illuminated regions. The mechanical properties of the films during UV light irradiation were investigated by classical rheology and, for the first time, by using amplitude modulation-frequency modulation atomic force microscopy (AM-FM AFM).

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“…[38][39] The values of the refractive index n were found systematically lower for the developed thin films (n = 1.61 at 650 nm for instance) compared to those determined before development (n = 1.80 at 650 nm) (see ESI - Figure S5a). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 15 the fact that photopolymerized layers loose compactness and gain free volume after development.…”

Section: Impact Of Photocrosslinking On the Density And Emission Propmentioning

confidence: 94%

All-Solution-Processed Organic Light-Emitting Diodes Based on Photostable Photo-cross-linkable Fluorescent Small Molecules

Derue

Olivier

Tondelier

et al. 2016

ACS Appl. Mater. Interfaces

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We demonstrate herein the fabrication of small molecule-based OLEDs where four organic layers from the hole- to the electron-transporting layers have successively been deposited by using an all-solution process. The key feature of the device relies on a novel photopolymerizable red-emitting material, made of small fluorophores substituted with two acrylate units, and displaying high-quality film-forming properties as well as high emission quantum yield as nondoped thin films. Insoluble emissive layers were obtained upon UV irradiation using low illumination doses, with no further need of postcuring. Very low photodegradation was noticed, giving rise to bright layers with a remarkable surface quality, characterized by a mean RMS roughness as low as 0.7 nm after development. Comparative experiments between solution-processed OLEDs and vacuum-processed OLEDs made of fluorophores with close architectures show external quantum efficiencies in the same range while displaying distinct behaviors in terms of current and power efficiencies. They validate the proof of concept of nondoped solution-processable emissive layers exclusively made of photopolymerized fluorophores, thereby reducing the amount of components and opening the way toward cost-effective fabrication of solution-processed OLED multilayer architectures.

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Influence of extrinsic and intrinsic parameters onto the formation of surface relief gratings in polar azo molecular glasses

Cited by 9 publications

References 32 publications

Disperse and disordered: a mexylaminotriazine-substituted azobenzene derivative with superior glass and surface relief grating formation

Disperse and disordered: a mexylaminotriazine-substituted azobenzene derivative with superior glass and surface relief grating formation

Direct observation of athermal photofluidisation in azo-polymer films

All-Solution-Processed Organic Light-Emitting Diodes Based on Photostable Photo-cross-linkable Fluorescent Small Molecules

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