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Fluorescent light modulation by small electric potentials has gained huge interest in the past few years. This phenomenon, called electrofluorochromism, is of the utmost importance for applications in optoelectronic devices. Huge efforts are being addressed to developing electrofluorochromic systems with improved performances. One of the most critical issue is their low cyclability, which hampers their widespread use. It mostly depends on the intrinsic reversibility of the electroactive/fluorophore molecular system and on device architecture. Here we show a novel fluorene-based mixed-valence electrofluorochromic system that allows direct electrofluorochromic switching and exhibits incomparable electrochemical reversibility and device cyclability of more than 10 000 cycles.

Four trigonal topology compounds with three diarylamines redox centers and dibenzofulvene as core bridge have been synthesized. Their radical cations exhibit appealing intramolecular electron transfer pathways between three redox centers, depending on their position on the core bridge. By changing such positions (on either 2,7- or 3,6-), and the length of the bridge, the control of the intramolecular electron transfer pathways was achieved through the electron self-exchange route. These processes were investigated by absorption spectroscopy, electron paramagnetic resonance spectroscopy, and (time-dependent) density functional theory calculations. Hole mobility measurements were carried out as well, to correlate the intramolecular electron transfer with the hole-transporting ability for possible applications in optoelectronic devices.

Calcium carbonate-based hollow or porous particles are one of the preferred carriers for fabrication of drug delivery systems. We have developed an eco-friendly method to produce calcium carbonate nanocrystals, which have shown biocompatibility and optimal capacity to across cell membrane in human cell lines providing new tools in cancer therapy. The success of drug delivery systems has paved the way for the development of systems for controlled release of agrochemicals. In this work, we exploited calcium carbonate nanocrystals as carriers for targeted release of phytodrugs investigating a potential control strategy for the pathogen Xylella fastidiosa. This pathogen is the causal agent of the Olive Quick Decline Syndrome that is an unprecedented emergency in Italy and potentially in the rest of Europe. We studied nanocrystals interactions with bacteria cells and the application in planta to verify olive plants uptake. Ultrastructural analysis by electron microscopy shown an alteration of bacteria wall following nanocrystals interaction. Nanocrystals were adsorbed from roots and they translocated in plants tissues. Calcium carbonate carriers were able to encapsulate efficiently two types of antimicrobial substances and the potential efficacy was tested in experiment under greenhouse conditions.

The photodynamic activity occurring through the lysosome photo-damage is effective in terms of triggered synergic effects which can avoid chemo-resistance pathways. The potential photodynamic activity of two fluorescent lysosome-specific probes was studied providing their interaction with human serum albumin, demonstrating their in vitro generation of singlet oxygen and investigating the resulted photo-toxic effect in human cancer cells.

Three new 2D-pi-A dyes (TK4, TK5 and TK6), composed of diarylamine donor groups, a dibenzofulvenethiophene core as the pi-bridge, and a cyanoacrylic acid anchoring group as the acceptor, have been successfully designed, synthesized, and characterized both experimentally and computationally. The performance in DSSC solar cells has been also studied. Octyloxy chains were introduced on the backbone of the dye, in order to increase donor capability, avoid aggregation side effects and increase physical insulation between electrolyte system and the TiO2 layer. The dye containing the octyloxy chains on the donor group and two thiophene ring as an extension of pi-bridge showed the best photovoltaic performance with a maximum of solar energy-to-electricity conversion yield of 7.8% under AM 1.5 irradiation (100 mW/cm(2)). (C) 2016 Elsevier Ltd. All rights reserved.

Three new metal-free organic dyes with the [1]benzothieno[3,2-b]benzothiophene (BTBT) π-bridge, having the structure donor-π-acceptor (D-π-A) and labeled as 19, 20 and 21, have been designed and synthesized for application in dye-sensitized solar cells (DSSC). Once the design of the π-acceptor block was fixed, containing the BTBT as the π-bridge and the cyanoacrylic group as the electron acceptor and anchoring unit, we selected three donor units with different electron-donor capacity, in order to assemble new chromophores with high molar extinction coefficients (ε), whose absorption features well reflect the good performance of the final DSSC devices. Starting with the 19 dye, which shows a molar extinction coefficient ε of over 14,000 M(-1) cm(-1) and takes into account the absorption maximun at the longer wavelength, the substitution of the BFT donor unit with the BFA yields a great enhancement of absorptivity (molar extinction coefficient ε > 42,000 M(-1) cm(-1)), until reaching the higher value (ε > 69,000 M(-1) cm(-1)) with the BFPhz donor unit. The good general photovoltaic performances obtained with the three dyes highlight the suitable properties of electron-transport of the BTBT as the π-bridge in organic chromophore for DSSC, making this very cheap and easy to synthesize molecule particularly attractive for efficient and low-cost photovoltaic devices.

In this work, we investigate the optical and structural properties of the well-known triplet emitter bis(4',6'-difluorophenylpyridinato)-iridium(III) picolinate (FIrpic), showing that its ability to pack in two different ordered crystal structures promotes attractive photophysical properties that are useful for solid-state lighting applications. This approach allows the detrimental effects of the nonradiative pathways on the luminescence performance in highly concentrated organic active materials to be weakened. The remarkable electro-optical behavior of sky-blue phosphorescent organic light-emitting diodes incorporating crystal domains of FIrpic, dispersed into an appropriate matrix as an active layer, has also been reported as well as the X-ray diffraction, nuclear magnetic resonance, electro-ionization mass spectrometry, and scanning electron microscopy analyses of the crystalline samples. We consider this result as a crucial starting point for further research aimed at the use of a crystal triplet emitter in optoelectronic devices to overcome the long-standing issue of luminescence self-quenching.

The synthesis of thiophene fluorophores (TFs) and the engineering of molecular structure to achieve bright and stable blue to red and white fluorescence are described. Examples of application of TFs in cellular studies are reported.

We show here that the recently reported surprisingly large association constant (K = 7.6 x 10(4) M(-1)) between azulene and [60]fullerene is due to experimental artifacts, pointing out potential errors in the characterization of association equilibria by fluorescence spectroscopy, and suggesting the best experimental practices.

The relative contributions of several weak intermolecular forces to the overall stability of the complexes formed between structurally related receptors and [60]fullerene are compared, revealing a discernible contribution from concave–convex complementarity. Viruela Martin, Pedro Manuel, Pedro.M.Viruela@uv.es ; Viruela Martin, Rafael, Rafael.Viruela@uv.es ; Orti Guillen, Enrique, Enrique.Orti@uv.es