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Blue-Shifting Intramolecular Charge Transfer Emission by Nonlocal Effect of Hyperbolic Metamaterials
Lee, Kwang Jin,Lee, Yeon Ui,Fages, Fré,dé,ric,Ribierre, Jean-Charles,Wu, Jeong Weon,D’Alé,o, Anthony American Chemical Society 2018 NANO LETTERS Vol.18 No.2
<P>Metallic nanostructures permit controlling various photophysical processes by coupling photons with plasmonic oscillation of electrons confined in the tailored nanostructures. One example is hyperbolic metamaterial (HMM) leading to an enhanced spontaneous emission rate of emitters located nearby. Noting that emission in organic molecules is from either pi-pi* or intramolecular charge-transfer (ICT) states, we address here how HMM modifies ICT emission spectral features by comparing them with a spectral shift dependent on the local polarity of the medium. The 7.0 nm blue shift is observed in ICT emission from 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran dispersed into a polymer matrix prepared on HMM multilayered structure, while no spectral shift is observed in pi-pi* emission from perylene diimide. In the frame of the Lippert-Mataga formalism, the blue shift is explained by the HMM nonlocal effects resulting from 8% decrease in refractive index and 18% reduction in dielectric permittivity. This phenomenon was also shown in a hemi-curcuminoid borondifluoride dye yielding 15.0 nm blue shift. Such a capability of spectral shift control in films by HMM structure opens new prospects for engineering organic light-emitting devices.</P>
Dental biomaterials for chairside CAD/CAM: State of the art
Hugo Lambert,Jean-Cédric Durand,Bruno Jacquot,Michel Fages 대한치과보철학회 2017 The Journal of Advanced Prosthodontics Vol.9 No.6
The wide use of chairside CAD/CAM restorations has increased the diversity of the restorative material. For the practitioner, the selection of the appropriate material is difficult amongst the variety offered by the market. Information on the characteristics of the products can be difficult to assess due to the lack of up-to-date classification and the lack of reliability of manufacturer’s advertising. The purpose of this article is to structure the data on restorative materials provided by various sources in order for the practitioner to choose the product mostsuited to the clinical situation. The objective is to classify chairside CAD/CAM materials and to define their characteristics and indications.
O. Gutierrez,R. Balart,D. Lascano,L. Quiles-Carrillo,E. Fages,L. Sanchez-Nacher 한국섬유공학회 2020 Fibers and polymers Vol.21 No.5
This work is focused on the upgrading olive oil pomace to obtain high environmentally friendly insulationmaterials for the construction and building industry. Upgrading of these wastes has been carried out by using the wet-laidtechnology in combination with different thermoplastic binder fibers both from natural and synthetic origin. After the wetlaidprocess, the obtained veils or non-wovens were subjected to different processes: a hot-press moulding process or acontinuous lamination process. The acoustic insulation properties were obtained by the Kundt’s tube while the thermalinsulating properties were obtained through determining heat transmission resistance (R) and heat absorption parameter (λ). These tests have revealed the excellent insulation properties of the olive pomace-derived materials, specifically, those basedon high surface density non-wovens. The complementary process that follows wet-laid, i.e. hot-press moulding orcontinuous lamination process has a remarkable effect on insulation behaviour. In particular, the hot-pressed materials fromolive pomace show better acoustic insulation while the continuously laminated materials offer the best thermal insulationproperties.
p-Type and n-type quaterthiophene based semiconductors for thin film transistors operating in air?
C. Videlot-Ackermann,J. Zhang,J. Ackermann,H. Brisset,Y. Didane,P. Raynal,A. El Kassmi,F. Fages 한국물리학회 2009 Current Applied Physics Vol.9 No.1
The solution and solid-state properties as well as the organic thin film transistor (OTFT) behavior of α,ω-perfluorohexyl-quaterthiophene (DFH-4T) are presented and compared to those of quaterthiophene (4T) and α,ω-hexyl-quaterthiophene (DH-4T). UV/visible and fluorescence data showed the same weak effect of hexyl and perfluorohexyl substitutions on the optical properties of 4T core. Growth mechanism of DFH-4T based thin films deposited by vacuum deposition on heated Si/SiO2 substrates has been investigated in details and demonstrated to be identical to that of DH-4T. The characterization in air of the charge transport properties of thin films based on DH- 4T and DFH-4T revealed a switch from p- to n-type, respectively, depending on the nature of alkyl chains. A qualitative Schottky-type charge injection barrier model, based on HOMO and LUMO energy levels estimated from cyclic voltammograms and optical absorption spectra of DFH-4T relative to those of 4T and DH-4T, was introduced to explain such change in semiconducting properties observed under ambient conditions (temperature, light, air). In an attempt to answer to the question of ‘‘are p-type and n-type quaterthiophene derivatives appropriate semiconductors for thin film transistors operating in air?” we investigated the influence of the nature of the dielectrics to obtain OTFTs operating in air and showing environmentally stable mobility. The solution and solid-state properties as well as the organic thin film transistor (OTFT) behavior of α,ω-perfluorohexyl-quaterthiophene (DFH-4T) are presented and compared to those of quaterthiophene (4T) and α,ω-hexyl-quaterthiophene (DH-4T). UV/visible and fluorescence data showed the same weak effect of hexyl and perfluorohexyl substitutions on the optical properties of 4T core. Growth mechanism of DFH-4T based thin films deposited by vacuum deposition on heated Si/SiO2 substrates has been investigated in details and demonstrated to be identical to that of DH-4T. The characterization in air of the charge transport properties of thin films based on DH- 4T and DFH-4T revealed a switch from p- to n-type, respectively, depending on the nature of alkyl chains. A qualitative Schottky-type charge injection barrier model, based on HOMO and LUMO energy levels estimated from cyclic voltammograms and optical absorption spectra of DFH-4T relative to those of 4T and DH-4T, was introduced to explain such change in semiconducting properties observed under ambient conditions (temperature, light, air). In an attempt to answer to the question of ‘‘are p-type and n-type quaterthiophene derivatives appropriate semiconductors for thin film transistors operating in air?” we investigated the influence of the nature of the dielectrics to obtain OTFTs operating in air and showing environmentally stable mobility.
Lee, K. J.,Woo, J. H.,Kim, E.,Xiao, Y.,Su, X.,Mazur, L. M.,Attias, A.-J.,Fages, F.,Cregut, O.,Barsella, A.,Mathevet, F.,Mager, L.,Wu, J. W.,D'Alé,o, A.,Ribierre, J.-C. The Royal Society of Chemistry 2016 Physical chemistry chemical physics Vol.18 No.11
<P>We investigate the photophysical properties of organic donor-acceptor dyad and triad molecular systems based on triphenylene and perylene diimide units linked by a non-conjugated flexible bridge in solution using complementary optical spectroscopy techniques. When these molecules are diluted in dichloromethane solution, energy transfer from the triphenylene to the perylene diimide excited moieties is evidenced by time-resolved fluorescence measurements resulting in a quenching of the emission from the triphenylene moieties. Simultaneously, another quenching process that affects the emission from both donor and acceptor units is observed. Solution ultrafast transient absorption measurements provide evidence of photo-induced charge transfer from either the donor or the acceptor depending upon the excitation. Overall, the analysis of the detailed time-resolved spectroscopic measurements carried out in the dyad and triad systems as well as in the triphenylene and perylene diimide units alone provides useful information both to better understand the relations between energy and charge transfer processes with molecular structures, and for the design of future functional dyad and triad architectures based on donor and acceptor moieties for organic optoelectronic applications.</P>
Š,tefane, Bogdan,Pož,gan, Franc,Kim, Eunsun,Choi, Eunyoung,Ribierre, Jean-Charles,Wu, Jeong Weon,Ponce-Vargas, Miguel,Le Guennic, Boris,Jacquemin, Denis,Canard, Gabriel,Zaborova, Elena,Fages Applied Science Publishers 2017 Dyes and pigments Vol.141 No.-
<P><B>Abstract</B></P> <P>The synthesis, characterization and (TD)-DFT calculations of the electrochemical and photophysical properties of novel ethynylene-analogues of hemicurcuminoids are described. These dyes are both emissive in solution and in the solid state. While compounds that emit through an efficient charge transfer (CT) state show solvatochromic behaviour associated with low fluorescence quantum yields, those lacking of donor groups show high fluorescence quantum yields of 70–80%, in solution. The latter dyes also present the advantage to emit in the solid state in the visible region with fluorescence quantum yields up to 23%. Their condensed phase spectrum can be bathochromically shifted to the near infrared region (742 nm) by appending a strong donor group.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesis of new fluorophores based on hemicurcuminoid boron difluoride. </LI> <LI> Photophysical study reveals strong emission of the dyes not containing charge transfer states. </LI> <LI> Fluorescence properties of dyes in their condensed phase show aggregation induced emission. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Felouat, Abdellah,D’Alé,o, Anthony,Charaf-Eddin, Azzam,Jacquemin, Denis,Le Guennic, Boris,Kim, Eunsun,Lee, Kwang Jin,Woo, Jae Heun,Ribierre, Jean-Charles,Wu, Jeong Weon,Fages, Fré,dé American Chemical Society 2015 The Journal of physical chemistry A Vol.119 No.24
<P>Controlling photoinduced intramolecular charge transfer at the molecular scale is key to the development of molecular devices for nanooptoelectronics. Here, we describe the design, synthesis, electronic characterization, and photophysical properties of two electron donor–acceptor molecular systems that consist of tolane and BF<SUB>2</SUB>-containing curcuminoid chromophoric subunits connected in a T-shaped arrangement. The two π-conjugated segments intersect at the electron acceptor dioxaborine core. From steady-state electronic absorption and fluorescence emission, we find that the photophysics of the dialkylamino-substituted analogue is governed by the occurrence of two closely lying excited states. From DFT calculations, we show that excitation in either of these two states results in a distinct shift of the electron density, whether it occurs along the curcuminoid or tolane moiety. Femtosecond transient absorption spectroscopy confirmed these findings. As a consequence, the nature of the emitting state and the photophysical properties are strongly dependent on solvent polarity. Moreover, these characteristics can also be switched by protonation or complexation at the nitrogen atom of the amino group. These features set new approaches toward the construction of a three-terminal molecular system in which the lateral branch would transduce a change of electronic state and ultimately control charge transport in a molecular-scale device.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpcafh/2015/jpcafh.2015.119.issue-24/acs.jpca.5b03699/production/images/medium/jp-2015-03699g_0001.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp5b03699'>ACS Electronic Supporting Info</A></P>
Ye, Hao,Kim, Dae Hyeon,Chen, Xiankai,Sandanayaka, Atula S. D.,Kim, Jong Uk,Zaborova, Elena,Canard, Gabriel,Tsuchiya, Youichi,Choi, Eun Young,Wu, Jeong Weon,Fages, Fré,dé,ric,Bredas, Jean-L American Chemical Society 2018 Chemistry of materials Vol.30 No.19
<P>Near-infrared (NIR) organic light-emitting devices have aroused increasing interest because of their potential applications such as information-secured displays, photodynamic therapy, and optical telecommunication. While thermally activated delayed fluorescent (TADF) emitters have been used in a variety of high-performance organic light-emitting diodes (OLEDs) emitting in the visible spectral range, efficient NIR TADF materials have been rarely reported. Herein, we designed and synthesized a novel solution-processable NIR TADF dimeric borondifluoride curcuminoid derivative with remarkable photophysical, electroluminescence and amplified spontaneous emission properties. This dye was specifically developed to shift the emission of borondifluoride curcuminoid moiety toward longer wavelengths in the NIR region while keeping a high photoluminescence quantum yield. The most efficient OLED fabricated in this study exhibits a maximum external quantum efficiency of 5.1% for a maximum emission wavelength of 758 nm, which ranks among the highest performance for NIR electroluminescence. In addition, this NIR TADF emitter in doped thin films displays amplified spontaneous emission above 800 nm with a threshold as low as 7.5 μJ/cm<SUP>2</SUP>, providing evidence that this material is suitable for the realization of high-performance NIR organic semiconductor lasers.</P> [FIG OMISSION]</BR>