Abstract: Molecular-level control of charge transfer is paramount for organic electronics and solar-energyconversion. Electromagnetic interactions, originating from the second strongest fundamental force in the universe, occur between charged particles. As electrostatic analogues of magnets, molecular electrets are dielectrics that contain ordered electric dipoles. We have demonstrated the utility of anthranilamides as suitable candidates for the bioinspired approach in the design of molecular electrets. Much like protein helices, anthranilamides, composed of non-native beta amino acids, possess intrinsic dipole moments originating from ordered amide and hydrogen bonds. Unlike the protein helices, however, anthranilamides have a backbone of directly linked aromatic moieties comprising pathways for highly efficient electron and hole transfer. The distal sites, i.e., the fourth and fifth position in the aromatic rings, provide a means for tuning the electronic properties of the electrets via chemical modifications. The dipole-generated local

fields of the bioinspired molecular electrets rectify the kinetics of charge separation and charge recombination. That is, the rates of electron transfer along the dipole are different from the rates against the dipole. Because our focus is on hole-transfer electrets, we need a suitable electron

acceptor for photoinitiating long-range charge transfer, providing the motivation for the design and development of such light sensitizers. To be able to harvest the energy from the sun, we choose sensitizers that absorb in the red, green and blue region of the spectrum, i.e., corroles,

diketopyrrolopyrrolo and fluorescent nitropyrenes. Such broad use of the light across the visible region of the electromagnetic spectrum will open avenues toward tandem light harvesting devices. In this presentation I will focus on our newly discovered fluorescence from

nitropyrenes. Pyrenes are the most used organic photoprobes. Upon nitration, pyrene exhibits a shift in its absorption to the visible spectral region. While the nitro group makes it a better electron acceptor, the nitropyrene is non-fluorescent due to efficient triplet formation. Amidating

the nitropyrene to produce NO2-Py -C(O)-NH-R did not eliminate the intersystem crossing. Recently, we discovered that inversion of the amides suppresses triplet formation and makes nitropyrene fluorescent. Reorienting the amide bond with the nitrogen adjacent to the pyrene

(NO2-Py-NH-C(O)-R) elevates the energy levels of the T2 and T3 states above that of the S1 state, resulting in the suppression of intersystem crossing. It results in fluorescence quantum yields as high as 0.26. This approach for modifying energy levels of excited states via relatively

straight forward chemical changes sets an important precedent not only for energy science, but also for organic electronics and photonics.

Abstract: Microalgal biomass has recently become increasingly significant as an alternative source for renewable fuels. Nevertheless, microalgae harvesting is one of the main barriers in its application for biofuels production, mostly due to the high costs involved with infrastructure and energy consumption. This work evaluated the energy expenditure of the cultivation, harvesting and drying stages of marine microalgae Nannochloropsis gaditana, a resistant species over a wide range of stress conditions. For the biomass harvesting step, centrifugation, cross flow filtration followed by centrifugation and coagulation-flocculation followed by centrifugation were performed in a lab scale. The drying step was evaluated by tests in a vacuum oven and lyophilizing the algal biomass. The calorific value of N. gaditana and moisture content of the biomass after the harvesting procedure were determined. Among the processing conditions, the cross flow filtration followed by vacuum drying required 0,06 kWh/L, showing overall smaller energy consumption. In addition, the cross flow filtration demanded a minor processing time and is able to reduce the volume 1.5 times, showing a higher efficiency in recovering algal biomass. The higher heating value of dried N.gaditana was 11.8 (±0.05) MJ/kg. In other works from our research group, where CO2 was bubbled through the sample, a 19.7 MJ/kg value was obtained. This suggests that this biomass can achieve superior calorific values and be applied in cogeration systems, due to its high energetic potential when compared to other biomasses, such as wood (18,6 MJ/kg). The selection of the best technique to harvest algal biomass depends on the strain, its size, cell density, physiological state, and bioproduct. Therefore, the obtained results suggest a possible strategy to reduce the energetic consumption at production and processing stages for N. gaditana biomass harvesting, with cross flow filtration occurring previously to the centrifugation step.

Abstract: Due to the growing demand for energy along with the concern with the emission of polluting gases in the atmosphere, the creation of renewable energy sources has become quite encouraged around the world. In this context, biofuels are important figures. Therefore, this lecture will to present results about a thermodynamic analysis, based in the DFT and canonical ensemble models of the biokerosene mixed in the JP-8 fuel (aviation kerosene) for several mix rates. For this study we simulate the JP-8 composition, as well as, with two kinds of biokerosene: coconut and palm oils. We obtained the following thermodynamic properties and the fuel total energy produced for the engine.

Abstract: In this presentation, an overview will be given of the research in our group in the Department of Applied Physics at CINVESTAV-Mérida (Yucatán, México) on the application of nanomaterials in a variety of solar energy systems, including photovoltaics, solar fuels, and solar-thermal energy conversion. In photovoltaics, the efforts in our group are focused on the dye-sensitized solar cell (DSC) and the hybrid perovskite solar cell (PSC), which are both based on a mesoporous, nanostructured metal oxide substrate. We have investigated the influence of the nanomaterials properties on the performance of the solar cells, using TiO2 in both the anatase and brookite form, and ZnO prepared by a variety of methods and with a range of morphologies. We also are making progress in the scale-up of the technology fabricating mini-modules of 24 cm2, reaching an efficiency of 4.8% for the DSCs based on anatase (in active area). In perovskite solar cell research we focus on low-temperature preparation methods for compact and mesoporous TiO2 films in order to prepare PSCs on flexible substrates; initial results are promising. We also aim to use NiO nanoparticles as a contact material on the p-side of the PSC in order to improve the mechanical properties of the device, and initial results will be presented. In the solar fuels research project, we use a combinatorial technique to find new metal oxide nanomaterials for solar water splitting. In addition, we use advanced (photo)electrochemical methods in order to study the fundamental processes taking place in promising nanomaterials. Recent work has shown interesting results for the p-type semiconductor CuBi2O4, and we have analyzed the hole transport and recombination properties using intensity-modulated methods, including photovoltage (IMPV) and photocurrent spectroscopy (IMPS). In addition, we have investigated water oxidation on WO3 electrodes in detail, using the same techniques for electron transport measurements. In the solar-to-thermal project, we focus on selective coatings that efficiently absorb sunlight but with a low thermal emittance, thus optimizing the conversion efficiency and minimizing loss processes. We use both electrodeposition and sputtering to prepare selective coatings, using cermet and multilayer stack approaches in order to tailor the optical properties of the thin films. Specific examples for Ni and Co black, and Mo-MoOx-Al2O3 systems will be presented.