Giuseppina Anna Corrente

New organic dyes based on a dibenzofulvene bridge for highly efficient dye-sensitized solar cells

Three novel organic dyes, coded TK1, TK2 and TK3, incorporating two donor moieties, cyanoacrylic acid as an acceptor/anchoring group, the dibenzofulvene core and an oligothiophene spacer in a 2D–π–A system, were designed, synthesized, and successfully utilized in dye-sensitized solar cells. The dye TK3, containing two thiophene rings as spacers, shows an IPCE action spectrum with a high plateau from 390 nm to 600 nm, increased open-circuit photovoltage by 40 mV and short-circuit photocurrent by 7.03 mA cm−1, with respect to TK1. Using CDCA as the co-adsorbent material, the Jsc of TK3 was increased to 14.98 mA cm−1 and a strong enhancement in the overall conversion efficiency (7.45%) was realized by TK3 compared to TK1 (1.08%), in liquid electrolyte-based DSSCs.

Enhanced Photocatalytic Activity of Pure Anatase Tio2 and Pt-Tio2 Nanoparticles Synthesized by Green Microwave Assisted Route

High-yield, rapid and facile synthesis of elongated pure anatase titania nanoparticles has been achieved through a nonaqueous microwave-based approach. The residual organics onto nanoparticles surfaces were completely removed through a new treatment under ozone flow, at room temperature in air. Such an ozone cleaning method revealed an effective inexpensive dry process of removing organic contaminants from nanoparticles surfaces. The TiO2 elongated nanoparticles having a length of 13.8 ± 5.5 nm and a diameter of 9.0 ±1.2 nm were characterized by powder X-Ray diffraction, transmission electron microscopy, selected area diffraction, BET surface area analyzer and FT-IR spectroscopy. Photocatalytic evaluation demonstrated that the as-synthesized ozone-cleaned TiO2 nanoparticles and TiO2 nanoparticles loaded with platinum possess excellent Rhodamine B performance with respect to both commercial spherical nanotitania P25 and P25 loaded with platinum. This could be attributed to the anatase phase purity, small size, large specific surface area and clean surfaces of the prepared nanoparticles.

Thiophene-based fluorescent probes with low cytotoxicity and high photostability for lysosomes in living cells.

BACKGROUND Selective imaging of lysosomes by fluorescence microscopy using specific fluorescent probes allows the study of biological processes and it is potentially useful also for diagnosis. Lysosomes are involved in numerous physiological processes, such as bone and tissue remodeling, plasma membrane repair, and cholesterol homeostasis, along with cell death and cell signaling. Despite the great number of dyes available today on the market, the search for new fluorescent dyes easily up-taken by cells, biocompatible and bearing bright and long-lasting fluorescence is still a priority. METHODS Two thiophene-based fluorescent dyes, TC1 and TC2, were synthetized as lysosome-specific probes. RESULTS The new dyes showed high selectivity for fluorescent staining and imaging of lysosomes and disclosed high photostability, low toxicity and pH insensitivity in the range 2-10. CONCLUSIONS The TC dyes exhibited high co-localization coefficients (>95%) and moderate quantum yields. They showed high biocompatibility and long-term retention, important features for biological applications. GENERAL SIGNIFICANCE The results of the present work disclose a new class of organic dyes with potential wide applications as specific and efficient lysosome probes in the study of various biological processes.

Effects of donor position on dibenzofulvene-based organic dyes for photovoltaics

A series of push–pull organic dyes based on the cyanoacrylic acid as the acceptor/anchoring group, a dibenzofulvene (DBF) connected with thienyl rings as the π-bridge, and donor units linked to different positions of the DBF molecule were synthetized and studied. The effects of the donor position on optical and photovoltaic properties were investigated through photophysics, electrochemical and photovoltaic measurements. The results uphold photovoltaic performances largely depend on the electronic structure of the dyes with a synergistic interaction between donor and acceptor groups. In detail, a fine tuning of the photophysical properties can be reached simply selecting the position of the donor unit on the DBF molecule. In particular, the dyes bearing the donor unit on the 3,6-positions of the DBF show better performances in term of light absorption and cell efficiency with respect to the dyes with the donor unit on the 2,7-positions.