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CZTS (Cu2ZnSnS4), a P-type semiconductor with a direct bandgap (1.2–1.7eV), earth-abundant, non-toxic, and has a large absorption coefficient makes it extremely useful in optoelectronics and light-harvesting applications. In this work, CZTS is prepared by an ingenious, cost-effective colloidal route using the ‘hot-injection’ method with the usage of different ligands. The XRD and Raman spectroscopy shows the single-phase highly crystalline CZTS nanoparticles with kesterite structure. The TEM results show that the size of CZTS nanoparticles is about 2–5 nm and monodispersity is confirmed by DLS (Dynamic Light Scattering). FTIR confirms the presence of different ligands used in CZTS preparation. The Uv–vis absorption shows the direct bandgap of 1.5–1.7eV. The contact angle study shows the hydrophobic nature of as-synthesized CZTS nanoparticles which were further ligand exchanged with l -cysteine hydrochloride to make it hydrophilic to study the photocatalytic degradation activity of organic pollutants and industrial waste in the water. The photocatalysis experiments were performed under two conditions: (i) under bare sunlight (Intensity ∼ 900 W/m2) (ii) focussing the sample under the sunlight via converging lens (1800 W/m2). The photocatalytic efficiencies were then compared and the best photocatalytic efficiency achieved under sunlight was 98.4% for organic pollutants and 75% for industrial waste via converging lens while the corresponding efficiencies with bare sunlight were 98.1% and 73% respectively. To the best of the author’s knowledge, a rapid and highly efficient photocatalysis of CZTS NPs employing a converging lens for water-remediation without the usage of noble & transition-metals has been reported for the first time.

An exemplary vision to understand the fundamental role of metal-doped multi-components system such as Au/Ag doped CZTS (Cu

In this article, the beneficial effect of surface passivation rendered by the amalgamation of co-ordinating tri-n-octylphophine (TOP), oleylamine (OLA), and oleic acid mixture on the structural and optoelectronic properties of lead selenide (PbSe) quantum dots (QDs) (~6–20 nm) and its respective poly(3-hexylthiophene) (P3HT) polymer: PbSe composites has been demonstrated. Here, OLA ligand is found to play a major role in the nucleation and growth mechanism and hence control of the size distribution of the resultant PbSe QDs. The superior quality of the OLA-passivated PbSe QDs can be attributed to its better homogeneity, colloidal and photostability, which it imparts to its respective polymer: PbSe composites as compared to the corresponding OA-passivated PbSe QDs. The role of post-synthesis ligand exchange/removal has been envisaged to facilitate efficient charge transport in hybrid composites and has been modeled pictorially. Accordingly, P3HT: PbSe (OLA) composites exhibit significant PL quenching and hence higher current and better charge transfer characteristics as compared to their OA-counterparts. An exhaustive structural, optical and electrical investigations as corroborated by various complimentary techniques (TEM/SEM, XRD, NMR, FTIR, NIR-Absorption, PL, XPS, and I-V) have resulted in some significant findings wherein the effective stabilizing and etching properties with an optimum binding capability of OLA ligands to PbSe surface are found to be imperative for its effective utilization in hybrid composite photovoltaic devices. The superior morphology, optical properties, and higher stability of OLA-capped PbSe QDs can aid in the proper understanding of efficient charge separation and transport in hybrid organic–inorganic nanocomposites solar cells based on colloidal PbSe nanocrystals.

BackgroundSARS-CoV-2 is a viral pathogen causing life-threatening disease in human. Interaction between spike protein of SARS-CoV-2 and ACE2 receptor on the cells is a potential factor in the infectivity of a host. The interaction of SARS-CoV-2 spike receptor-binding domain with its receptor - ACE2, in different hosts was evaluated to understand and predict viral entry. The protein and nucleotide sequences of ACE2 were initially compared across different species to identify key differences among them. The ACE2 receptor of various species was homology modeled (6LZG, 6M0J, and 6VW1 as a reference), and its binding ability to the spike ACE2 binding domain of SARS-CoV-2 was assessed. Initially, the spike binding parameters of ACE2 of known infected and uninfected species were compared with each Order (of animals) as a group. Finally, a logistic regression model vis-a-vis the spike binding parameters of ACE2 (considering data against 6LZG and 6M0J) was constructed to predict the probability of viral entry in different hosts.ResultsPhylogeny and alignment comparison did not lead to any meaningful conclusion on viral entry in different hosts. Out of several spike binding parameters of ACE2, a significant difference between the known infected and uninfected species was observed for six parameters. However, these parameters did not specifically categorize the Orders (of animals) into infected or uninfected. The logistic regression model constructed revealed that in the mammalian class, most of the species of Carnivores, Artiodactyls, Perissodactyls, Pholidota, and Primates had high probability of viral entry. However, among the primates, African Elephant had low probability of viral entry. Among rodents, hamsters were highly probable for viral entry with rats and mice having a medium to low probability. Rabbits have a high probability of viral entry. In Birds, ducks have a very low probability, while chickens seemed to have medium probability and turkey showed the highest probability of viral entry.ConclusionsMost of the species considered in this study showed high probability of viral entry. This study would prompt us to closely follow certain species of animals for determining pathogenic insult by SARS-CoV-2 and for determining their ability to act as a carrier and/or disseminator.

Genomics-led researches are engaged in tracing virus expression pattern, and induced immune responses in human to develop effective vaccine against COVID-19. In this study, targeted expression profiling and differential gene expression analysis of major histocompatibility complexes and innate immune system genes were performed through SARS-CoV-2 infected RNA-seq data of human cell line, and virus transcriptome was generated for T-and B-cell epitope prediction. Docking studies of epitopes with MHC and B-cell receptors were performed to identify potential T-and B-cell epitopes. Transcriptome analysis revealed the specific multiple allele expressions in cell line, genes for elicited induce immune response, and virus gene expression. Proposed T- and B-cell epitopes have high potential to elicit equivalent immune responses caused by SARS-CoV-2 infection which can be useful to provide links between elicited immune response and virus gene expression. This study will facilitate in vitro and in vivo vaccine related research studies in disease control., Highlights • SARS-CoV-2 transcriptome construction from RNA-seq data of infected human cell-lines. • T- and B-cell epitopes from SARS-CoV-2 transcriptome • Gene expression profiling of MHC alleles and innate immune system genes

Solar photovoltaic (PV) is empowering, reliable, and ecofriendly technology for harvesting energy which can be assessed from the fact that PV panels with total electricity generation capacity of 505 GW have been installed by the end of 2018. Thin-film solar cells based on copper indium gallium selenide (CIGSe) are promising photovoltaic absorber material owing to an alternative to crystalline silicon (c-Si)-based solar cells because of the huge potential for low-cost solar electricity production with minimal usage of raw materials. The efficiency record of 23.4% was achieved recently in CIGSe solar cells, which was comparable to c-Si solar cells (27.6%). The manufacturing cost of $0.34/W is expected for 15% efficient CIGSe module. The present review article discusses the perspectives of CISe/CIGSe-based thin-film solar cells with the focus on absorber material. Different vacuum and non-vacuum techniques for fabricating these materials are discussed along with the operation of solar cells and their manufacturability. The working mechanism of CIGSe solar cells with the characteristic features of the open-circuit voltage and current density as well as the factors influencing the efficiency in different fabrication techniques are reviewed. Moreover, some strategies toward the improvement of solar cells performance contemplating modified deposition are reviewed. Furthermore, how these strategies can be executed in order to make it cost effective methods is also discussed in detail. Prevailing constrictions for the commercial maturity are deliberated, and future perspectives for improvement at lab as well as industrial scalabilities are outlined.

NBS-LRR comprises a large class of disease resistance (R) proteins that play a widespread role in plant protection against pathogens. In grapevine, powdery mildew cause significant losses in its productivity and efforts are being directed towards finding of resistance loci or genes imparting resistance/tolerance against such fungal diseases. In the present study, we performed genome-wide analysis of NBS-LRR genes during PM infection in grapevine. We identified 18, 23, 12, 16, 10, 10, 9, 20 and 14 differentially expressed NBS-LRR genes in response to PM infection in seven partially PM-resistant (DVIT3351.27, Husseine, Karadzhandal, Khalchili, Late vavilov, O34–16, Sochal) and 2 PM-susceptible (Carignan and Thompson seedless) V. vinifera accessions. Further, the identified sequences were characterized based on chromosomal locations, physicochemical properties, gene structure and motif analysis, and functional annotation by Gene Ontology (GO) mapping. The NBS-LRR genes responsive to powdery mildew could potentially be exploited to improve resistance in grapes.

Quaternary chalcopyrite, i.e., Cu2ZnSnS4 (CZTS) nanoparticles films have been proposed as a novel matrix system for enzyme-based electrochemical biosensors providing a non-toxic, low-cost alternative for the fabrication of bioelectrodes. The easy tuneability of the band gap of CZTS by varying the cation ratio and size of nanoparticles facilitate to impart desirable electrical properties in the material. Butylamine capped spherical CZTS nanoparticles of size 15–16 nm and band gap 2.65 eV have been synthesized by colloidal hot injection technique. The films of CZTS onto ITO substrates are deposited using dip coating technique, and uricase enzyme have been immobilized onto CZTS films using EDC-NHS binding chemistry. Electrochemical analyses of this bioelectrode revealed that the uricase/CZTS/ITO/glass electrode exhibits good linearity over a wide range of 0–700 μM uric acid concentration with a limit of detection (LOD) of 0.066 µM. The low value of 0.13 × 10−4 M of Michaelis–Menten constant (Km) indicate the enhanced affinity of immobilized enzyme (uricase) towards uric acid. Thus, the present report confirms the promising application of the p-type CZTS thin film matrix for the realization of an electrochemical biosensor.

У роботі наночастинки оксиду олова (SnO2), відпалені при температурах 400, 500 та 600 °C, були підготовлені методом твердотільної реакції. Структурні та оптичні властивості підготовлених наночастинок SnO2 аналізували за допомогою рентгенівського дифрактометра (XRD) та скануючого електронного мікроскопа (SEM). Елементне дослідження було виконано енергетично-дисперсійною рентгенівською спектроскопією (EDAX), інфрачервоною спектроскопією з використанням перетворення Фур'є (FTIR), методами динамічного розсіювання світла (DLS) та поглинання світла в ультрафіолетовому та видимому діапазонах (UV-Vis). Рентгенівська дифрактограма підтверджує чисту тетрагональну структуру рутилу наночастинок SnO2 без будь-якої домішкової фази. SEM зображення відображають утворення нанострижнів при всіх температурах відпалу 400, 500 і 600 °C, тоді як EDAX аналіз підтверджує наявність Sn і O без будь-яких домішок. UV-Vis спектри показують, що ширина забороненої зони підготовлених наночастинок SnO2 спочатку зменшується з 3,44 еВ при температурі 400 °С до 3,03 еВ при 500 °С, а потім збільшується до 3,39 еВ при температурі 600 °С. Спектр FTIR підтверджує наявність зв'язку O–Sn–O разом з одним небажаним піком поглинання. In the present work, nanoparticles of tin oxide (SnO2) annealed at temperatures of 400 °C, 500 °C, and 600 °C were prepared via solid-state reaction method. Structural and optical properties of prepared SnO2 nanoparticles were analyzed by X-ray diffractometer (XRD), scanning electron microscope (SEM), elemental study was performed by energy-dispersive X-ray spectroscopy (EDAX), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) and ultraviolet-visible (UV-Vis) absorption characterizing techniques. The X-ray diffraction pattern confirms the pure tetragonal rutile structure of tin oxide nanoparticles without any impurity phase. SEM images depict the formation of nanorods at all annealing temperatures of 400 °C, 500 °C, and 600 °C while EDAX analysis confirms the presence of Sn and O without any impurities. UV-Vis absorption spectra show that the band gap of prepared tin oxide nanoparticles decreases initially from 3.44 eV at 400 °C to 3.03 eV at 500 °C and further increases to 3.39 eV at 600 °C. FTIR spectrum confirms the presence of O–Sn–O bond along with one unwanted absorption peak.

In this work, stable Cu2ZnSnS4 (CZTS) nanocrystals (NCs) in pure kesterite phase were synthesized by a facile one-pot rapid injection technique (colloidal route). Time-dependent reaction mechanism for the synthesis of CZTS nanoparticles is explained. When TOP-S (Tri-octyl phosphine–sulphur) was injected in the CuZnSn-complex with TOPO (Tri-octyl phosphine oxide) as capping ligand, orthorhombic phase Cu2−XS nanoparticles of spherical shape were found at nucleation sites. With an advancement in the reaction time, Sn got infused in Cu2−XS to form Cu2SnS3 and its shape got deformed. Further increase in reaction time infuses Zn to form Cu2ZnSnS4 with the gradual vanishing of Cu2−XS and Cu2SnS3 phases and finally, the rod-shaped CZTS Np’s were obtained. This factor of reaction time, which influence the morphology and size were studied in detail. The structural and optical properties of the pure kesterite phase CZTS nanorods were also analysed. The band gap of the rod-like CZTS is determined to be around 1.43 eV, which is an optimum value for solar photoelectric conversion.

Wet-route synthesis of CuInSe2 (CISe) nanocrystals has been envisaged with the utilization of the unique combination of coordinating ligand and non coordinating solvent. Our work demonstrates the formation of a single-phase, nearly stoichiometric and monodispersive, stable and well-passivated colloidal ternary CISe nanocrystals (band gap (Eg)~1.16 eV) using a novel combination of ligands; viz. volatile arylamine aniline and non-volatile solvent 1-octadecene. The synthesis and growth conditions have been manoeuvred using the colligative properties of the mixture and thus higher growth temperature (~250 °C) could be attained that promoted larger grain growth. The beneficial influence of the capping agents (aniline and 1-octadecene) on the properties of chalcopyrite nanocrystals has enabled us to pictorally model the structural, morphological and optoelectronic aspects of CISe nanoparticles.

In this work, we have demonstrated the structural and optoelectronic properties of the surface of ternary/quaternary (CISe/CIGSe/CZTSe) chalcopyrite nanocrystallites passivated by tri-n-octylphosphine-oxide (TOPO) and tri-n-octylphosphine (TOP) and compared their charge transfer characteristics in the respective polymer: chalcopyrite nanocomposites by dispersing them in poly(3-hexylthiophene) polymer. It has been found that CZTSe nanocrystallites due to their high crystallinity and well-ordered 3-dimensional network in its pristine form exhibit a higher steric- and photo-stability, resistance against coagulation and homogeneity compared to the CISe and CIGSe counterparts. Moreover, CZTSe nanocrystallites display efficient photoluminescence quenching as evident from the high value of the Stern–Volmer quenching constant (KSV) and eventually higher charge transfer efficiency in their respective polymer P3HT:CZTSe composites. We modelled the dependency of the charge transfer from the donor and the charge separation mechanism across the donor–acceptor interface from the extent of crystallinity of the chalcopyrite semiconductors (CISe/CIGSe/CZTSe). Quaternary CZTSe chalcopyrites with their high crystallinity and controlled morphology in conjunction with regioregular P3HT polymer is an attractive candidate for hybrid solar cells applications.

The Cu2O nanoparticles having average crystallite diameters ∼8–16 nm were synthesized by a simple solvothermal method. The Mn was doped in the Cu2O sample of crystallite size ∼8 nm. The effects of the size and doping concentration on the crystal structures of the nanoparticles were investigated. The x-ray photoelectron spectroscopy studies clearly showed that the Mn was incorporated into the Cu2O lattice as Mn2+ due to the substitution of the Cu+ ions by Mn2+ ions. The quantum confinement effects were observed in the nanoparticles. The multiple emissions from the Cu2O were quenched in the Mn doped nanoparticles and only blue light emitting Cu2O nanoparticles were obtained due to the transition T42→A61 of Mn. The effects of the doping concentration and the particle size on the relaxations dynamics of the Cu2O nanoparticles were mainly investigated using photoluminescence decay.

This letter demonstrates the effect of cadmium selenide (CdSe) quantum dots on hole transport in poly(3-hexylthiophene) (P3HT) thin films. Current-voltage characteristics of P3HT and P3HT:CdSe thin films have been studied in the temperature range of 288–85K, in hole only device configurations, i.e., indium tin oxide (ITO)/poly(ethylene-dioxthiophene):polystyrenesulphonate (PEDOT:PSS)/P3HT/Au and ITO/PEDOT:PSS/P3HT:CdSe∕Au. The incorporation of CdSe quantum dots in P3HT results in the enhancement in hole current and switches the transport from dual conduction mechanism, viz., trap and mobility models to only trap model. This is attributed to the reduction in characteristic trap energy from 60to32meV and trap density from 2.5×1018to1.7×1018cm−3.