Organic Materials Unit

Department Inorganic and Organic Chemistry, Faculty Chemisty

Research Areas: NanosMat

One of the major challenges of the research in the Organic Materials group will be the programming of different properties (optical, electronic, luminescent or magnetic) into liquid single crystal elastomers (LSCE), i.e. weakly cross-linked polymer networks that combine the elasticity of conventional rubbers with the long-range molecular order of liquid crystals, which reaches the macroscopic level. Unraveling the different structural and environmental factors that might influence the behavior of the active components in this medium is crucial to obtain actuators with the expected abilities, for example, efficient optical mechanotransducers (mechanical-optical field) with either inverse (fluorescence increases upon stretching of the LSCE) or multiple responses (emission intensity changes at two different wavelengths upon the application of a single mechanical force); effective artificial muscle-like actuators capable of experiencing sophisticated deformations upon suitable activation (optical-magnetic-mechanical field) or flexible electronic devices (electric-mechanical field).
Our research group has garnered a solid background in organic synthesis, macromolecular chemistry and materials chemistry and physics over the years. Specifically, and as a result of the research performed during the last projects, we have got experience in the design and synthesis of highly conjugated organic heterocycles with luminescent and semiconductor properties, and potential magnetic behaviour. The Organic Materials group investigates in the design and comprehension of the different factors that influence the semiconductor behaviour of organic materials and in the Interface engineering and solid-state organization for organic thin-film transistors. We are also engaged in the development of molecular and macromolecular liquid-crystalline systems for different applications. We have defined for the first time distinct mesogenic systems, based on the carbazole and porphyrin cores, with potential technological interest. Furthermore, light-sensitive azo derivatives have been introduced into liquid-crystalline elastomeric networks in order to produce efficient and rapid optically-controlled artificial muscle-like actuators. The latter research was funded by the European project “FUnctional Liquid-Crystalline Elastomers” (FULCE) of which Prof. Dr. h.c. H. Finkelmann, a worldwide leader in the field of macromolecular chemistry and physics, was its coordinator. On the other hand, the decoration of the azobenzene core with appropriate electron donating and electron withdrawing organic functions has led to the development of a wide palette of azo dyes endowed with switching speeds down to the nanosecond time window.

Programming Positive Mechanofluorescence in Liquid Crystalline Elastomers. Güixens-Gallardo P.; Brea I.; Manrique J.; Shohraty F.; Garcia-Amorós J.; Velasco D. 2023, ACS Applied Polymer Materials, 5, 8. Doi: 10.1021/acsapm.3c01050

Insight into the Diindolo[3,2-b:2′,3′-h]carbazole Core as an Air-Stable Semiconductor for OTFTs. Bujaldón R.; Vilche A.; Puigdollers J.; Puigjaner C.; Alcobé X.; Velasco D. 2023, ACS Applied Electronic Materials, 5, 7. Doi:10.1021/acsaelm.3c00412

Photochromic heteroarylethenes with fast thermal isomerization kinetics. Garcia-Amorós J.; Castro M.C.R.; Raposo M.M.M.; Velasco D. 2023, Dyes and Pigments, 210, 111000. Doi: 10.1016/j.dyepig.2022.111000

Powder X-ray diffraction as a powerful tool to exploit in organic electronics: shedding light on the first N,N′,N′′-trialkyldiindolocarbazole. Vilche A., Bujaldon R., Alcobe X., Velasco D., Puigjaner C. Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials, 78, 253, 260, 2022

Low-molar-mass and oligomeric derivatives of carbazole and triphenylamine containing thiazolo[5,4-d]thiazole moieties. Dabuliene A., Dainyte A., Andruleviciene V., Lygaitis R., Punniyakoti S.M., Tomkeviciene A., Velasco D., Obushak M., Grazulevicius J.V. Polymer Bulletin, 2022

Exploring the 3-(phenylethynyl)-9H-carbazole unit in the search of deep-blue emitting fluorophores; R. Bujaldón, N. Peřinka, M. Reig, A. Cuadrado, C. Fabregat, M. Font-Bardía, E. Martínez-Ferrero, D. Velasco; Optical Materials, 2021, 111, 110696.

Towards the bisbenzothienocarbazole core: a route of sulfurated carbazole derivatives with assorted optoelectronic properties and applications; R. Bujaldón, J. Puigdollers, D. Velasco, Materials, 2021, 14, 3487, doi.org/103390/mat14133487.

Structural features guiding the design of liquid-crystalline elastomeric fluorescent force sensors; J. Garcia-Amorós, D. Velasco, Applied Systems Innovation, 2020, 3, 22 (invited review).

Shedding light on the negative differential resistance effect observed in organic thin-film transistors; E. Ros, M. Reig, C. Voz, G. Bagdziunas, P. Ortega, D. Velasco, J. Puigdollers, ACS Applied Electronic Materials, 2020, 2, 1574-1582.

Picosecond switchable azo dyes; J. Garcia-Amorós, B. Maerz, M. Reig, A. Cuadrado, Ll. Blancafort, E. Samoylova, D. Velasco, Chemistry – A European Journal, 2019, 25, 7726-7732.

Adaptable photochromic switches with self-aggregating heterocyclic azo dyes; J. Garcia-Amorós, M. C. R. Castro, S. Nonell, S. Vílchez, J. Esquena, M. M. M. Raposo, D. Velasco, Journal of Physical Chemistry C, 2019, 123, 23140-23144.

High-pressure kinetics of azo dyes in nematic liquid crystals; J. Garcia-Amorós, M. Martínez, D. Velasco, Journal of Physical Chemistry C, 2019, 123, 30578-30583.

Highly efficient elastomeric fluorescence sensors for force detection; D. Heras, M. Reig, N. Llorca-Isern, J. Garcia-Amorós, D. Velasco, ACS Applied Polymer Materials, 2019, 1, 535-541.

Formation of a stable biradical triplet state cation versus a closed shell singlet state cation by oxidation of adducts of 3,6-dimethoxycarbazole and polychlorotriphenylmethyl radicals; P. Ballesteros, A. Cuadrado, A. Gilabert, L. Fajarí, I. Sirés, E. Brillas, M. P. Almajano, D. Velasco, J. M. Anglada, L. Julià, Physical Chemistry Chemical Physics, 2019, 21, 20225-20231.

Bipolar charge transport in organic electron donor-acceptor systems with stable organic radicals as electron-withdrawing moieties; A. Bobet, A. Cuadrado, L. Fajarí, I. Sirés, E. Brillas, M. P. Almajano, V. Jankauskas, D. Velasco, L.Juliá, Journal of Physical Organic Chemistry, 2019, 32, e3974.