Kohat University of Science and Technology

Perovskite solar cells represent the third generation of solar cell technology and have garnered significant research attention due to their low cost and high efficiency. Researchers have taken a keen interest in further enhancing their efficiency and improving their stability. This paper reports the use of tin sulfide (SnS) as a hole transport layer (HTL) in lead-free methylammonium tin iodide (MASnI(3)) perovskite solar cells. SnS is a cost-effective and nontoxic material with direct-bandgap energy. The device layers were structured as indium tin oxide (ITO)/TiO2/CH3NH3SnI3/SnS/Au. The structural performance was investigated using the SCAPS-1D one-dimensional solar cell simulation software under illumination of 1000 W/m(2) with air mass (AM) of 1.5. Absorber parameters including thickness, doping density, and defect density and their influence on the device performance were elaborated. In addition, the effects of temperature, thickness, and doping density of both the HTL and electron transport layer (ETL) were clarified. By optimizing these parameters for the HTL, ETL, and absorber layers, the simulation generated electron-hole pairs within the absorber. It was found that the holes migrated to the SnS HTL and the electrons migrated towards the TiO2 ETL. The carrier dynamics led to an open-circuit voltage (V-oc) of 0.95 V, a short-circuit current density (J(sc)) of 32.2 mA/cm(2), a fill factor (FF) of 83.04%, and maximum power conversion efficiency (PCE) of 25.58% at an initial temperature of 300 K. SnS was found to be a favorable HTL with methylammonium tin iodide (MASnI(3)), enabling low-cost fabrication while achieving maximum PCE of 25.58%.

DEAD-box RNA Helicases (RHs) have been proved effective in plants against stress conditions, increasing their tolerance to different environmental stresses. To date, many different studies have revealed the occurrence of these proteins in many plants; however, studies of DEAD-box RHs in wheat, particularly those targetted to chloroplast, are still waiting to be studied. In this article, we performed an extensive genome-wide analysis of DEAD-box RHs in wheat genome. The results revealed that wheat genome consists of 116 RHs that have been retrieved using https://plants.ensembl.org/index.html . Among the 116 DEAD-box RHs, 50 were found to have the DEAD motif. While 39, out of 50 were found predicted to be localized to chloroplast by analyzing amino acid sequence of the DEAD-box RHs using a web-based prediction server ( http://avermitilis.ls.kitasato-u.ac.jp/chlorop/) . These 39 DEAD-box RHs were found to have sequences of chloroplast transit peptide (cTP). The predicted chloroplast localized DEAD-box RHs were analyzed for their distribution on chromosome and found unevenly distributed across the 21 chromosomes of common bread wheat. DEAD-box RHs with more than 40 cTP length were selected and proceeded for the analysis of expression patterns under drought, heat, and salt stress conditions. The results revealed that TraHEN2, TraRH47a, TraRH47c, TraISE2 (6A, 6B), TraRH58, TraRH22 (5A, 5B, 5D), and TraRH39 (3A) were highly induced in heat stress, while the expressions of TraRH47 (a, and b), TraSTRS2 (3A), TraRH22 (5B, 5D) and TraRH39 (3A) were increased many folds under salt stress. Under drought stress the transcript level of TraRH47 (A, B), TraSTRS2 (3A), TraRH58, TraRH22 (5A, 5B) and TraRH39 were highly induced. However, expressions of TraRH33 remained reduced in all stresses. This study concludes that high induction of the mentioned DEAD-box RHs under drought, salt and heat play important role in wheat responses to abiotic stress conditions. The study may lead the foundation that over-expression of these genes in wheat and other crops may develop stress-resistance, which may lead to high yield and possibly meet the demands of the increasing population.

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