Advances in understanding the photoresponsive behavior of azobenzenes substituted with strong electron withdrawing groups

Jerca, Valentin Victor; Jerca, Florica Adriana; Rău, Ileana; Manea, Adrian; Vuluga, Dumitru Mircea; Kajzar, F.

doi:10.1016/j.optmat.2015.07.042

Cited by 25 publications

(14 citation statements)

References 35 publications

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“…On the other hand, for practical applications such as data storage and photochromic memory, a “two stable state system” is desired. 61,64 Attempts have been reported in the past to increase the cis-isomer’s lifetime. For example, the inclusion of azobenzene motifs in the main chain of a polyurethane enhances the cis-life by up to 4 days.…”

Section: Results and Discussionmentioning

confidence: 99%

Triptycene-Derived Photoresponsive Fluorescent Azo-Polymer as Chemosensor for Picric Acid Detection

et al. 2019

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Two new triptycene-based azobenzene-functionalized polymers ( TBAFPs ) have been synthesized using the well-known Pd-catalyzed Sonogashira cross-coupling polycondensation reaction between 2,6-diethynyltriptycene and ( meta or para ) dibromo-azobenzenes. Enhancement of the fluorescent emission intensity was observed upon trans → cis isomerization of −N=N― linkage in TBAFPs . The cis-lifetime of TBAFP1 is rather long (greater than 2 days). The resulting materials were tested as a potential chemosensor for the detection of picric acid (PA)—a water pollutant as well as chemical constituent of explosives used in warfare. PA was found to interact strongly with TBAFPs , which led to significant quenching of the latter’s fluorescence emission intensities. The binding constants are in the order of 10 5 M –1 . TBAFPs were also able to detect PA in nanomolar concentrations.

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Section: Results and Discussionmentioning

confidence: 99%

Triptycene-Derived Photoresponsive Fluorescent Azo-Polymer as Chemosensor for Picric Acid Detection

et al. 2019

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“…In addition to the intrinsic advantages of organic materials, such as low cost, mechanical flexibility, and chemical versatility, OPTs exhibit higher photosensitivity and lower noise than two-terminal organic photodiodes because the gate electrode, being the third terminal, enables charge carriers to be accumulated at the interface between the gate insulator and organic semiconductor layer, resulting in the amplification of output signals [1][2][3][4][5]. In these OPTs, the photoresponse can be simply tuned by adopting organic materials such as photochromes through photoisomerization of these molecules at different wavelengths and photoresponsive polymers [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Improvement of Photoresponse in Organic Phototransistors through Bulk Effect of Photoresponsive Gate Insulators

Park

Kim

2020

Materials

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In this study, we investigate the bulk effect of photoresponsive gate insulators on the photoresponse of organic phototransistors (OPTs), using OPTs with poly(4-vinylphenol) layers of two different thicknesses. For the photoresponse, the interplay between the charge accumulation (capacitance) and light-absorbance capabilities of a photoresponsive gate insulator was investigated. Although an OPT with a thicker gate insulator exhibits a lower capacitance and hence a lower accumulation capability of photogenerating charges, a thicker poly(4-vinylphenol) layer, in contrast to a thinner one, absorbs more photons to generate more electron–hole pairs, resulting in a higher photoresponse of the device. That is, in these two cases, the degree of light absorption by the photoresponsive gate insulators dominantly governed the photoresponse of the device. Our physical description of the bulk effect of photoresponsive insulators on the performance of OPTs will provide a useful guideline for designing and constructing high-performance organic-based photosensing devices and systems.

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“…Specifically, azobenzene chromophore can undergo trans ‐to‐ cis isomerization upon UV irradiation while the cis ‐to‐ trans isomerization occurs upon visible light irradiation or thermal relaxation . Previous evidence has indicated that the thermal relaxation of cis ‐isomer is highly dependent on temperature, solvents, and structures of azobenzene moiety . Photoinduced isomerization between nonpolar trans ‐ and polar cis ‐azobenzene chromophore frequently accompanies by physical property change (e.g., solubility) .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Properties of UCST‐Type Thermo‐ and Light‐Responsive Homopolypeptides with Azobenzene Spacers and Imidazolium Pendants

Zhao

Zhang

Zheng

et al. 2019

Macro Chemistry & Physics

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Homopolypeptide bearing azobenzene and triethylene glycol spacers, and 1‐butylimidazolium pendants, namely P(Azo‐OEG3‐ImX) (X = Cl, I, BF4) are prepared by 1,3‐dipolar cycloaddition and subsequent ion‐exchange reaction. Both 1H NMR and FTIR confirm the polymer structures and reveal a high grafting efficiency (97%). P(Azo‐OEG3‐ImI) shows reversible upper critical solution temperature (UCST)‐type thermoresponsive property in ethanol while P(Azo‐OEG3‐ImI/BF4) shows a UCST in ethanol/water solvent mixtures. P(Azo‐OEG3‐ImI) shows UCST‐type phase transitions in ethanol or ethanol/water solvent mixtures. After UV irradiation, the UCST‐type cloud point temperature (Tcp) remains constant in ethanol. However, it decreases after UV irradiation and increases after visible light irradiation in ethanol/water solvent mixtures due to the trans–cis isomerization of azobenzene moieties. P(Azo‐OEG3‐ImCl/I) shows NaI‐induced UCST in water. The Tcp of the P(Azo‐OEG3‐ImCl/I) aqueous solution is highly related to the polymer/salt concentration and nature of counteranions. P(Azo‐OEG3‐ImCl) also shows reversible light‐responsive properties in NaI aqueous solutions. Higher NaI concentration is needed to induce a UCST for P(Azo‐OEG3‐ImCl) after UV irradiation. Moreover, ciprofloxacin‐loaded hydrogel containing P(Azo‐OEG3‐ImCl) shows more efficient drug release while the UV irradiation leads to slightly low drug release.

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Advances in understanding the photoresponsive behavior of azobenzenes substituted with strong electron withdrawing groups

Cited by 25 publications

References 35 publications

Triptycene-Derived Photoresponsive Fluorescent Azo-Polymer as Chemosensor for Picric Acid Detection

Triptycene-Derived Photoresponsive Fluorescent Azo-Polymer as Chemosensor for Picric Acid Detection

Improvement of Photoresponse in Organic Phototransistors through Bulk Effect of Photoresponsive Gate Insulators

Synthesis and Properties of UCST‐Type Thermo‐ and Light‐Responsive Homopolypeptides with Azobenzene Spacers and Imidazolium Pendants

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