Comparative mitochondrial genomics of endemic Mexican vesper yellow bats genus Rhogeessa (Chiroptera: Vespertilionidae) and insights into internal relationships in the family Vespertilionidae.

In the species-rich family Vespertilionidae, vesper yellow bats in the genus Rhogeessa include eleven species, three of them endemic to Mexico. These insectivorous bats provide important ecosystem services, including pest control. Even though some aspects of their biology are well- known, only a few genomic resources are available for these species, which limits our understanding of their biology. In this study, we assembled and annotated the mitochondrial genome of four species: R. aenea, R. genowaysi, R. mira, and R. parvula. We generated a phylomitogenomic hypothesis based on translated protein-coding genes for a total of 52 species in the family Vespertilionidae and examined the phylogenetic position of the genus Rhogeessa and species within the family. The AT-rich mitogenomes of R. aenea, R. genowaysi, R. mira, and R. parvula are 16,763, 16,781, 16,807, and 16,794 pb in length, respectively. Each studied mitogenome encodes 13 Protein Coding Genes (PCGs), 22 transfer RNA genes, and 2 rRNA genes, and contains a putative control region (CR). All tRNAs exhibit a 'cloverleaf' secondary structure, except tRNA-Serine-1 that lacked the DHU arm in all studied mitogenomes. Selective pressure analyses indicated that all protein-coding genes are exposed to purifying selection. The phylomitogenomic analysis supported the monophyletic status of the family Vespertilionidae, confirmed the placement of Rhogeessa within the tribe Antrozoini, and clarified phylogenetic relationships within and among subfamilies and tribes in this family. Our results indicate that phylomitogenomics are useful to explore the evolutionary history of vesper bats. The assembly and comprehensive analysis of mitochondrial genomes offer the potential to generate molecular references and resources beneficial for genetic analyses aimed at understanding the ecology and evolution of these remarkable bats.

Sub-picosecond collapse of molecular polaritons to pure molecular transition in plasmonic photoswitch-nanoantennas.

Molecular polaritons are hybrid light-matter states that emerge when a molecular transition strongly interacts with photons in a resonator. At optical frequencies, this interaction unlocks a way to explore and control new chemical phenomena at the nanoscale. Achieving such control at ultrafast timescales, however, is an outstanding challenge, as it requires a deep understanding of the dynamics of the collectively coupled molecular excitation and the light modes. Here, we investigate the dynamics of collective polariton states, realized by coupling molecular photoswitches to optically anisotropic plasmonic nanoantennas. Pump-probe experiments reveal an ultrafast collapse of polaritons to pure molecular transition triggered by femtosecond-pulse excitation at room temperature. Through a synergistic combination of experiments and quantum mechanical modelling, we show that the response of the system is governed by intramolecular dynamics, occurring one order of magnitude faster with respect to the uncoupled excited molecule relaxation to the ground state.

Organic dye-sensitized solar cells containing alkaline iodide-based gel polymer electrolytes: influence of cation size.

The electrolyte used in dye-sensitized solar cells (DSSCs) plays a key role in the process of current generation, and hence the analysis of charge-transfer mechanisms both in its bulk and at its interfaces with other materials is of fundamental importance. Because of solvent confinement, gel polymer electrolytes are more practical and convenient to use with respect to liquid electrolytes, but in-depth studies are still necessary to optimize their performances. In this work, gel polymer electrolytes of general formulation polyacrylonitrile (PAN)/ethylene carbonate (EC)/propylene carbonate (PC)/MI, where M+ is a cation in the alkaline series Li-Cs, were prepared and used in DSSCs. Their ionic conductivities were determined by impedance analysis, and their temperature dependence showed Arrhenius behavior within the experimental window. FT-IR studies of the electrolytes confirmed the prevalence of EC coordination around the cations. Photo-anodes were prepared by adsorbing organic sensitizer D35 on nanocrystalline TiO2 thin films, and employed to build DSSCs with the gel electrolytes. Nanosecond transient spectroscopy results indicated a slightly faster dye regeneration process in the presence of large cations (Cs+, Rb+). Moreover, a negative shift of TiO2 flat-band potential with the decreasing charge density of the cations (increasing size) was observed through Mott-Schottky analysis. In general, results indicate that cell efficiencies are mostly governed by photocurrent values, in turn depending on the conductivity increase with cation size. Accordingly, the best result was obtained with the Cs+-containing cell, although in this case a slight reduction of photovoltage compared to Rb+ was observed.

Extending charge separation lifetime and distance in patterned dye-sensitized SnO2-TiO2 µm-thin films.

A simple method for the preparation of patterned dye-sensitized SnO2-TiO2 thin films, designed to prolong the lifetime of the interfacial charge separated state is presented. Using microfluidic technology, the thin films were sensitized with the organic sensitizer D35 such that they contain SnO2-TiO2 areas with dye and SnO2 dye-free areas at which injected electrons can be accumulated. Single wavelength transient absorption spectroscopy confirmed significantly extended charge separation lifetime at the dye-semiconductor interface. Sufficiently high density of injected electrons results in substantial decrease of charge recombination rate constants (kcr); a factor of ∼50 compared to dye-sensitized TiO2 thin films and a factor of ∼2000 compared to dye-sensitized SnO2 thin films. Furthermore, the potential of this approach was confirmed by photoinduced conduction band mediated electron transfer from the dye to a model electron acceptor, Co protoporphyrin IX, which was adsorbed to the SnO2-only regions.