Perovskite solar cells have gained immense interest from researchers owing to their good photophysical properties, low‐cost production, and high power conversion efficiencies. Hole transport ...materials (HTMs) play a dominant role in enhancing the power conversion efficiencies (PCEs) and long diffusion length of holes and electrons in perovskite solar cells. In hole transport materials, modification of π‐linkers has proved to be an efficient approach for enhancing the overall PCE of perovskite solar cells. In this work, π‐linker modification of a recently synthesized H−Bi molecule (R) is achieved with novel π‐linkers. After structural modifications, ten novel HTMs (HB1–HB10) with a D−π−D backbone are obtained. The structure–property relationship, and optoelectronic and photovoltaic characteristics of these newly designed hole transport materials are examined comprehensively and compared with reference molecules. In addition, different geometric parameters are also examined with the assistance of density functional theory (DFT) and time‐dependent DFT. All the designed molecules exhibit narrow HOMO–LUMO energy gaps (Eg=2.82–2.99 eV) compared with the R molecule (Eg=3.05 eV). The designed molecules express redshifting in their absorption spectra with low values of excitation energy, which in return offer high power conversion efficiencies. Further, density of states and molecular electrostatic potential analysis is performed to locate the different charge sites in the molecules. The reorganizational energies of holes and electrons are found to have good values, suggesting that these novel designed molecules are efficient hole transport materials for perovskite solar cells. In addition, the low binding energy values of the designed molecules (compared with R) offer high current charge density. Finally, complex study of HB9:PC61BM is also undertaken to understand the charge transfer between the molecules of the complex. The results of all analyses advocate that these novel designed HTMs are promising candidates for the construction of future high‐performance perovskite solar cells.
Perovskite solar cells: Advanced quantum chemical techniques are employed to explore the photophysical, photovoltaic, and optoelectronic properties as well as the structure–property relationship of R and HB1–HB10 molecules. The studied systems may be targeted for the development of high‐performance perovskite solar cells.
•Round robin with 7 partners for TGA of cellulose and beech wood pyrolysis.•Broad range of values reported in literature for activation energies in pyrolysis TGA.•Recommended method to reduce ...variability and increase reliability of derived kinetics.•Complementary use of isoconversional and model fitting methods for reliable kinetics.
The large variations found in literature for the activation energy values of main biomass compounds (cellulose, hemicellulose and lignin) in pyrolysis TGA raise concerns regarding the reliability of both the experimental and the modelling side of the performed works. In this work, an international round robin has been conducted by 7 partners who performed TGA pyrolysis experiments of pure cellulose and beech wood at several heating rates. Deviations of around 20 – 30 kJ/mol were obtained in the activation energies of cellulose, hemicellulose and conversions up to 0.9 with beech wood when considering all experiments. The following method was employed to derive reliable kinetics: to first ensure that pure cellulose pyrolysis experiments from literature can be accurately reproduced, and then to conduct experiments at different heating rates and evaluate them with isoconversional methods to detect experiments that are outliers and to validate the reliability of the derived kinetics and employed reaction models with a fitting routine. The deviations in the activation energy values for the cases that followed this method, after disregarding other cases, were of 10 kJ/mol or lower, except for lignin and very high conversions. This method is therefore proposed in order to improve the consistency of data acquisition and kinetic analysis of TGA for biomass pyrolysis in literature, reducing the reported variability.
•Net energy analysis of ethanol for India is 6 MJ/litre which is significantly lower than that reported for Brazil with value of 18 MJ/litre.•Net energy value of ethanol reduces from 6 MJ/litre to ...1.5 MJ/litre if irrigation energy is increased by 50%.•Gain in net energy value is negligible even with increase in cane productivity by 50% due to additional fertilizer application.•Optimizing water and fertilizer use is recommended to improve net energy value of ethanol.
Ethanol is being projected as a renewable future biofuel to be a total substitute for gasoline by policymakers in India. Today it is used in blended form with gasoline. Ethanol in India is produced from sugarcane in distilleries and most of those are integrated with sugar industries. Anecdotal evidence suggests that sugarcane production in India consumes lot of water and for irrigating the crop electricity is consumed. Electricity is produced from fossil fuel mainly coal in India. Quantifying the energy input that goes into sugarcane production and ethanol processing is therefore relevant. This paper reports the findings from field investigations into the energy use practices of sugarcane production in a sugarcane belt of Maharashtra and a study of energy use in sugar industry. Net energy value is reported in MJ per litre of Ethanol and is found to be 40% surplus. Similar studies are reported for Brazilian Ethanol by investigators. The key differences in net energy value in India and Brazil arise from the assumptions regarding cane growing practices including power required in pumped irrigation and fertilizer application per litre of ethanol production. Net energy analysis of biofuels depends on the data assumed by the researchers regarding input of energy use, source of energy, energy value of co-products and land and water productivity of sugar cane. Sensitivity analysis is therefore included to account for all these parameters.
Display omitted
Maize is the most widely spread energy source used in rations for farm animals and poultry, especially in countries in America, Southern Europe and Asia, where maize grain is the main cereal used for ...feed. The quality of maize grain is formed under the influence of several interrelated factors. The aim of the study is to determine the effect of different rates of nitrogen fertilization on the chemical composition and energy value of maize grain grown under irrigation conditions in non-ruminants. The study was conducted in the experimental field of the Agricultural Institute - Stara Zagora under irrigation conditions on cinnamon-meadow soil with maize for grain, medium late hybrid LG 35.36 with density of crops - 70000 plants per hectare. The study includes the following four treatments of fertilization: 1 experimental variant N0P80K60 – non-fertilizer control, 2 experimental variant N100P80K60 – fertilization with 100 kg N.ha-1, 3 experimental variant N150P80K60 – fertilization with 150 kg N.ha-1 and 4 experimental variant N200P80K60 – fertilization with 200 kg N.ha-1. Nitrogen fertilizer was applied during the vegetation of the crop in phase 3-5 leaf, and phosphorus and potassium fertilizers in rates 80 kg P2O5.ha-1 and 60 kg K2O.ha-1 in the main tillage. During the vegetation of the maize, pre-irrigation humidity of 80-85% of field capacity (FC) was maintained by 3 waterings. As the fertilization rate increases, the crude protein content in the maize grain also grows up. During the treatment with the highest fertilizer rate of 200 kg N.ha-1, 9.5% per 1 kg of dry matter (DM) was obtained, followed by the treatment with 150 kg N.ha-1 – with a value of 9.1% per 1 kg of dry matter. The content of crude fiber in the grain of maize with increasing fertilization rate decreases, being the smallest in the treatment with rate 100 kg N.ha-1 – 0.8% per 1 kg of dry matter. The fertilization rate does not have a significant effect on the content of digestible and metabolite energy in corn grain grown under irrigated conditions in pigs and poultry.
Display omitted
•ZnO, WO3, binary composite WO3-ZnO and ternary WO3-ZnO@rGO nanocomposites were prepared.•The minimum bandgap was 2.62 eV for WO3.•Maximum photocatalytic activity (i.e. > 90 %) was ...observed by rGO based composite.
Novel graphene supported ternary nanocomposites (WO3-ZnO@rGO) were prepared via simple ultrasound assisted fabrication of WO3-ZnO binary nanostructures over 2D rGO nanosheets. Structural, morphological and elemental characterization of as-synthesized samples were carried out through X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FE-SEM) and Energy dispersive X-ray spectroscopy (EDX). Optical band gap analysis under UV–vis spectroscopy (UV–vis) revealed a decrement in the band gap energy value of WO3-ZnO@rGO ternary nanocomposites. Current-voltage (I–V) measurements evidenced the ohmic response of rGO supported WO3-ZnO nanocomposites as compared to bare samples. To evaluate the photocatalytic efficiency of WO3-ZnO@rGO nanocomposites in comparison to bare nanostructures, wastewater organic pollutant methylene blue (MB) dye was chosen as benchmark reaction. Results suggested that impregnation of WO3-ZnO over rGO sheets significantly improved the photocatalytic efficiency of WO3-ZnO@rGO with 94 % dye removal within 90 min under visible light irradiation. The enhanced photocatalytic efficiency is ascribed to synergistic effects originating at WO3-ZnO@rGO interfaces subsidizing high quantum yield and effective separation and transfer of photo induced electron-hole pairs. Moreover, WO3-ZnO@rGO also retained its remarkable dye degradation efficiency even after four recycling tests.
PDF
