Roberto Termine

Bio: Roberto Termine is an academic researcher from University of Calabria. The author has contributed to research in topics: Photorefractive effect & Liquid crystal. The author has an hindex of 17, co-authored 53 publications receiving 859 citations. Previous affiliations of Roberto Termine include Spanish National Research Council.

High charge mobility in discotic liquid-crystalline triindoles: just a core business?

Abstract: This work has been supported by CTQ2007-65683/BQU, (CTQ2009- 09030), S2009/MAT-1756/CAM, MiUR through the PRIN 2007 (2007WJMF2W) project, Gobierno de Aragon, 200960I086 PIE.

New Electrode-Friendly Triindole Columnar phases with High Hole Mobility

Abstract: A new class of conducting discotic liquid crystals is identified in recently synthesized derivatives of heptacyclic triindole, which combine the hole transport properties of the carbazole unit with...

H-Bonded Donor-Acceptor Units Segregated in Coaxial Columnar Assemblies: Toward High Mobility Ambipolar Organic Semiconductors

Abstract: A novel approach to ambipolar semiconductors based on hydrogen-bonded complexes between a star-shaped tris(triazolyl)triazine and triphenylene-containing benzoic acids is described. The formation of 1:3 supramolecular complexes was evidenced by different techniques. Mesogenic driving forces played a decisive role in the formation of the hydrogen-bonded complexes in the bulk. All of the complexes formed by nonmesogenic components gave rise to hexagonal columnar (Colh) liquid crystal phases, which are stable at room temperature. In all cases, X-ray diffraction experiments supported by electron density distribution maps confirmed triphenylene/tris(triazolyl)triazine segregation into hexagonal sublattices and lattices, respectively, as well as remarkable intracolumnar order. These highly ordered nanostructures, obtained by the combined supramolecular H-bond/columnar liquid crystal approach, yielded donor/acceptor coaxial organization that is promising for the formation of ambipolar organic semiconductors with...

High hole mobility in triindole-based columnar phases: Removing the bottleneck of homogeneous macroscopic orientation

Abstract: We report the synthesis, mesomorphic behavior, and mobility values of a series of highly ordered N-substituted triindole-based columnar liquid crystals. Shortening the length of N-alkylic substituents from N-dodecyl to N-methyl chains results in a drastic approach of the disks within the columns and in an impressive increase in charge carrier mobility. An study of aggregation in solution provide insights into the intermolecular forces responsible of the reduction of the intrastack distance as the size of the N-alkyl chains is decreased and offer evidence of stabilization of the columns by the contribution of cooperative CH−π interactions. The materials presented here exhibit mobility values, even in totally misaligned columnar phases, that may compete with those of the best polycrystalline organic semiconductors, without the need of costly vacuum evaporation processes.

Not Only Columns: High Hole Mobility in a Discotic Nematic Mesophase Formed by Metal-Containing Porphyrin-Core Dendrimers

Abstract: We report a new family of multifunctional liquid-crystalline porphyrin-core dendrimers that have coumarin functional groups around the porphyrin core. Porphyrin metalation strongly affects the photophysical properties, and therefore ZnII and CuII derivatives have also been prepared. All the synthesized dendrimers form a nematic discotic mesophase. Their high tendency for homeotropic alignment makes these dendrimers excellent candidates for device applications, owing to their easy processability, spontaneous alignment between electrodes, and self-healing of defects because of their dynamic nature. The charge mobility values of these materials are the highest ever reported for a nematic discotic phase. Moreover, these values are similar to the highest values reported for ordered columnar mesophases, and this shows that a supramolecular organization in columns is not necessary to achieve high charge mobility.

Organic photoresponse materials and devices

Abstract: Organic photoresponse materials and devices are critically important to organic optoelectronics and energy crises. The activities of photoresponse in organic materials can be summarized in three effects, photoconductive, photovoltaic and optical memory effects. Correspondingly, devices based on the three effects can be divided into (i) photoconductive devices such as photodetectors, photoreceptors, photoswitches and phototransistors, (ii) photovoltaic devices such as organic solar cells, and (iii) optical data storage devices. It is expected that this systematic analysis of photoresponse materials and devices could be a guide for the better understanding of structure–property relationships of organic materials and provide key clues for the fabrication of high performance organic optoelectronic devices, the integration of them in circuits and the application of them in renewable green energy strategies (critical review, 452 references).

Discotic Liquid Crystals for Opto-Electronic Applications †,‡

Abstract: Discotic liquid crystals (DLCs) have been exploited in opto-electronic devices for their advantageous properties including long-range self-assembling, self-healing, ease of processing, solubility in a variety of organic solvents, and high charge-carrier mobilities along the stacking axis. An overview of DLCs and their charge-carrier mobilities, theoretical modeling, alignment, and device applications is addressed herein. The effects of alignment on charge-carrier properties of DLCs are discussed. Particular attention is devoted to processing techniques that achieve suitable alignment of DLCs for efficient electronic devices such as zone-casting, zone melting, Langmuir−Blodgett deposition, solution-casting on preoriented polytetrafluoroethylene (PTFE), surface treatment, IR irradiation, application of a magnetic field, use of sacrificial layers, use of blends, application of an electric field, and others.