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Abstract Three-dimensional (3D) metal halide perovskite solar cells (PSCs) have a power conversion efficiency that is now comparable with conventional silicon solar cells. For PSC applications to succeed in the market, long-term reliability under open-air conditions is essential. Recent experiments have shown that two-dimensional (2D) perovskites seem to exhibit good stability due to the presence of hydrophobic organic spacers, but 2D PSCs are incapable of generating and transporting a large amount of charge due to their extended optical bandgaps. Mixed dimensional perovskites with dimension lies between 2D and 3D recently became a promising candidate to sustain long-term stability and high performances concurrently to address this obstacle. The current research article presents the finding of simulation-based studies performed on novel device architecture consisting of ITO/Nb-Ti2O3/3D Perovskite/2D Perovskite/Spiro-OMeTAD/Au. Using optical simulation features of SCAPS, absorption of light is computed in the proposed device. The computational results show that the thickness of the 2D perovskite layer badly affects the solar cell parameters. A thin 2D perovskite behaves as a capped coating that avoids the deterioration of 3D perovskite in open-air environments. The effect of a multivalent defect in the 3D perovskite layer is mathematically modelled, and their impact on overall performance parameters are analyzed. The findings are compared to the same configuration results, except where the absorber layer’s multivalent defect has been substituted by a neutral defect of the same defect density of about (1011 cm−3). Results show that the multivalent defect leads to an underestimation of the efficiency by 4.2%.

The study evaluates the potential of different vegetable wastes namely, composite vegetable waste (CVW), potato waste (PW), sweet potato waste (SPW) and yam waste (YW) as an alternative feedstock for the production of renewable sugars. Thermal assisted chemical pretreatment followed by enzymatic saccharification yielded maximum sugars (0.515 g/g CVW, 0.56 g/g PW, 0.57 g/g SPW and 0.56 g/g YW) with total carbohydrate depolymerization of 95.01%, 88.30%, 90.32% and 88.59% respectively. Obtained sugars were valorized into bioethanol through fermentation using S. cerevisiae by optimizing the pH and temperature. The highest ethanol yield of 251.85 mg/g was obtained from SPW at 35°C followed by YW (240.98 mg/g), PW (235.4 mg/g) and CVW (125.6 mg/g) at pH 5.0. Utilizing the abundantly available vegetable wastes as a renewable feedstock for reducing sugars and subsequent bioethanol production will influence the economics and sustainability of the process positively in circular biorefinery format.

The development of photobioreactor is important for sustainable production of renewable fuels, wastewater treatment and CO2 fixation. For the design and scale-up of a photobioreactor, CFD can be used as an indispensable tool. The present study reviews the recent status of computational flow modelling of various types of photobioreactors, involving fluid dynamics, light transport, and algal growth kinetics. An integrated modelling approach of hydrodynamics, light intensity, mass transfer, and biokinetics in photobioreactor is discussed further. Also, this reviews intensified system to improve the mixing, and light intensity of photobioreactors. Finally, the prospects and challenges of CFD modelling in photobioreactors are discussed. Multi-scale modelling approach and development of low-cost efficient computational framework are the areas to be considered for modelling of photobioreactor in near future. In addition, it is necessary to use process intensification techniques for photobioreactors for improving their hydrodynamics, mixing and mass transfer performances, and algal growth productivity.

Bioethanol is one of the alternatives of the conventional fossil fuel. In present study, effect of different carbon sources on the production of cellulolytic enzyme (CMCase) from Trichoderma reesei at different temperatures, duration and pH were investigated and conditions were optimized. Acid treated Kans grass (Saccharum sponteneum) was subjected to enzymatic hydrolysis to produce fermentable sugars which was then fermented to bioethanol using Saccharomyces cerevisiae. The maximum CMCase production was found to be 1.46 U mL(-1) at optimum condition (28°C, pH 5 and cellulose as carbon source). The cellulases and xylanase activity were found to be 1.12 FPU g(-1) and 6.63 U mL(-1), respectively. Maximum total sugar was found to be 69.08 mg/g dry biomass with 20 FPU g(-1) dry biomass of enzyme dosage under optimum condition. Similar results were obtained when it was treated with pure enzyme. Upon fermentation of enzymatic hydrolysate, the yield of ethanol was calculated to be 0.46 g g(-1).

The choice of hole-transport materials (HTMs) has a strong impact on electric field-induced degradation of perovskite solar cells (PSCs). Rational design of HTMs is necessary to make PSCs sufficiently stable for the targeted practical applications.

Surfactants play major role in the delignification of lignocellulosic biomass. Surfactant-assisted hydrothermal pretreatment was evaluated for chili post-harvest residue. Maximum reducing sugar yield of 0.445 g per g of dry biomass (g/g) was obtained when surfactant PEG 6000 was used. Compositional analysis revealed an efficient removal of lignin and hemicelluloses from the pretreated biomass. Fermentation inhibitors such as furfural, 5-hydroxymethylfurfural and organic acids were absent in the hydrolyzate. After pretreatment, the biomass can be directly hydrolyzed without any neutralization, washing and drying, and the hydrolyzate is devoid of major fermentation inhibitors. Fermentation with Saccharomyces cerevisiae yielded 1.84% of ethanol with a fermentation efficiency of 63.88%.

Quorum-sensing molecules (QSMs) extracted from anaerobic sludge can help to enhance the overall productivity of algal culture, thus diminishing the per unit production cost of algae based-biofuel. In this investigation, QSMs extracted from anaerobic bacterial sludge of microbial fuel cell (MFC) was used to enhance the overall productivity of Chlorella sorokiniana cultivated in a separate bubble column photobioreactor. With the dosage of QSMs, algal biomass productivity and lipid content were increased by 2.25 times and 1.28 times, respectively. Further, lipid extracted biomass of quorum-sensing induced algae (LEB-QSA) was applied in anodic chamber of MFC to function as substrate and mediator, which enhanced the coulombic efficiency of this MFC by 74% as compared to the control MFC operated without LEB-QSA. Thus, this exploration demonstrated successful improvement in the macromolecular properties of algal culture dosed with QSMs and improved performance of MFC with the application of LEB-QSA as mediator and substrate.

Abstract Now-a-days a large number of extensive research has been focused on electrochromic oxide thin films, owing to their potential applications in smart windows, low cost materials in filters, low cost electrochemical devices and also in solar cell windows. Among the varieties of electrochromic transition metal oxides, the molybdenum oxide (MoO 3 ) and tungsten oxide (WO 3 ), form a group of predominant ionic solids that exhibit electrochromic effect. The electrochromic response of these materials are aesthetically superior to many other electrochromic materials, because WO 3 and MoO 3 absorb light more intensely and uniformly. In the present case, we have discussed about the electrochromic behaviour of electron beam evaporated MoO 3 films. Moreover, the MoO 3 film can also be used as a potential electro-active material for high energy density secondary lithium ion batteries; because it exhibits two-dimensional van der Waals bonded layered structure in orthorhombic phase. The films were prepared by evaporating the palletized MoO 3 powder under the vacuum of the order of 1 × 10 −5 mbar. The electrochemical behaviour of the films was studied by intercalating/deintercalating the K + ions from KCl electrolyte solutions using three electrode electrochemical cell by the cyclic-voltammetry technique. The studies were carried out for different scanning rates. The films have changed their colour as dark blue in the colouration process and returns to the original colour while the bleaching process. The diffusion coefficient values ( D ) of the intercalated/deintercalated films were calculated by Randle's Servcik equation. The optical transparency of the coloured and bleached films was studied by the UV–Vis–NIR spectrophotometer. The change in bonding assignment of the intercalated MoO 3 films was studied by FTIR spectroscopic analysis. A feasible study on the effect of substrate temperatures and annealing temperatures on optical density (OD) and colouration efficiency of the films were discussed and explored their performance for the low cost electrochemical devices.