The primary objectives of modern agriculture includes the environmental sustainability, low production costs, improved plants’ resilience to various biotic and abiotic stresses, and high sowing seed value. Delayed and inconsistent field emergence poses a significant threat in the production of agri-crop, especially during drought and adverse weather conditions. To open new routes of nutrients’ acquisition and revolutionizing the adapted solutions, stewardship plans will be needed to address these questions. One approach is the identification of plant based bioactive molecules capable of altering plant metabolism pathways which may enhance plant performance in a brief period of time and in a cost-effective manner. A biostimulant is a plant material, microorganism, or any other organic compound that not only improves the nutritional aspects, vitality, general health but also enhances the seed quality performance. They may be effectively utilized in both horticultural and cereal crops. The biologically active substances in biostimulant biopreparations are protein hydrolysates (PHs), seaweed extracts, fulvic acids, humic acids, nitrogenous compounds, beneficial bacterial, and fungal agents. In this review, the state of the art and future prospects for biostimulant seedlings are reported and discussed. Biostimulants have been gaining interest as they stimulate crop physiology and biochemistry such as the ratio of leaf photosynthetic pigments (carotenoids and chlorophyll), enhanced antioxidant potential, tremendous root growth, improved nutrient use efficiency (NUE), and reduced fertilizers consumption. Thus, all these properties make the biostimulants fit for internal market operations. Furthermore, a special consideration has been given to the application of biostimulants in intensive agricultural systems that minimize the fertilizers’ usage without affecting quality and yield along with the limits imposed by European Union (EU) regulations.

The dearth of n -type sulfides with thermoelectric performance comparable to that of their p- type analogues presents a problem in the fabrication of all-sulfide devices. Chalcopyrite (CuFeS 2 ) offers a rare example of an n -type sulfide. Chemical substitution has been used to enhance the thermoelectric performance of chalcopyrite through preparation of Cu 1- x Sn x FeS 2 (0 ≤ x ≤ 0.1). Substitution induces a high level of mass and strain field fluctuation, leading to lattice softening and enhanced point-defect scattering. Together with dislocations and twinning identified by transmission electron microscopy, this provides a mechanism for scattering phonons with a wide range of mean free paths. Substituted materials retain a large density-of-states effective mass and, hence, a high Seebeck coefficient. Combined with a high charge-carrier mobility and, thus, high electrical conductivity, a 3-fold improvement in power factor is achieved. Density functional theory (DFT) calculations reveal that substitution leads to the creation of small polarons, involving localized Fe 2+ states, as confirmed by X-ray photoelectron spectroscopy. Small polaron formation limits the increase in carrier concentration to values that are lower than expected on electron-counting grounds. An improved power factor, coupled with substantial reductions (up to 40%) in lattice thermal conductivity, increases the maximum figure-of-merit by 300%, to zT ≈ 0.3 at 673 K for Cu 0.96 Sn 0.04 FeS 2 .

Structural stability, electronic structure and optical properties of CH3NH3BaI3 hybrid perovskite is examined from theory as well as experiment. Solution-processed thin films of CH3NH3BaI3 exhibited a high transparency in the wavelength range of 400 nm to 825 nm (1.5 eV to 3.1 eV for which the photon current density is highest in the solar spectrum) which essentially justifies a high bandgap of 4 eV obtained by theoretical estimation. Also, the XRD patterns of the thin films match well with the {00l } peaks of the simulated pattern obtained from the relaxed unit cell of CH3NH3BaI3, crystallizing in the I4/mcm space group, with lattice parameters, a = 9.30Å, c = 13.94Å. Atom projected density of state and band structure calculations reveal the conduction and valence band edges to be comprised primarily of Barium d -orbitals and Iodine p-orbitals, respectively. The larger band gap of CH3NH3BaI3 compared to CH3NH3PbI3 can be attributed to the lower electro-negativity coupled with the lack of d -orbitals in the valence band of Ba 2+ . A more detailed analysis reveals the excellent chemical and mechanical stability of CH3NH3BaI3 against humidity, unlike its lead halide counterpart, which degrades under such conditions. We propose La to be a suitable dopant to make this compound a promising candidate for transparent conductor applications, especially for all perovskite solar cells. This claim is supported by our calculated results on charge concentration, effective mass and vacancy formation energies.PACS numbers: 81.10.Dn, 61.50.Ah, 61.10.Nz, 42.70.Qs, Recently, compounds in the organic-inorganic halide perovskite family (AB X 3 : A is an organic cation, B is an inorganic cation, and X is a halide element) have garnered a lot of attention in the solar photovoltaic community. This is due to their superior optoelectronic properties, easy synthesis techniques and variety of compounds that can be obtained via simple substitutions of the A, B and X ions. Specifically, solar cells, with (CH 3 NH 3 ) + as the A cation and Pb 2+ as the B cation, have shown a rapid growth in the solar-to-electricity power conversion efficiency.1-5 The lead halide perovskite solar cell was first introduced by Kojima et al in 2009, wherein it was used in a dye-sensitized solar cell architecture.6 Much of the research in recent times has focused on solid-state cells with different architectures, hole transport layers, compositional engineering, and synthesis techniques.1,3,7-10 Even then, there are some caveats associated with the various components of the CH 3 NH 3 PbX 3 -based solar cells: the stability of the absorber material in ambient conditions and the presence of Pb to name a couple. Active research to address these problems is being conducted worldwide through suitable replacements to both the CH 3 NH 3 and Pb cations.Tunability of the properties by changing the constituent elements gives this class of material more scope of research and applicability.11-13 Such tunability in the bandgap has been observed in the oxide perovskites, wher...

Rapid discovery of potential functional materials remains an open challenge. We often focus on exploring the properties of previously reported compounds, but avoid various unreported but chemically plausible compounds that might have promising properties. Here, we present a high throughput ab initio study of the I-III-IV class of half-Heusler alloys with 8 valence electrons, in the quest of finding potential (i) thermoelectric, (ii) topological insulating, and (iii) optoelectronic materials. Of various classes, 8electron half-Heusler compounds are least studied, and hence our choice. By carefully choosing reliable and accurately simulated descriptors (such as formation energy, phonon dispersion, accurate band gaps), we have discovered 21 semiconducting compounds. Out of these 21 compounds, 6 were found to show excellent thermoelectric performance (figure of merit ZT > 0.8); other range from ZT = 0.2 to 0.8. Seventeen compounds were found to show robust topological insulating behavior confirmed by bulk band inversion, and surface conducting states. Two compounds show a relatively large band gap and can be promoted for possible optoelectronic applications with further band engineering. Our search model opens new avenues for the discovery of more novel materials in different and unexplored classes of systems. We strongly propose the experimental characterization of the above promising compounds to shed more light on the present findings.

Herein an ewly discovered non-polar solvent based synthesis of MAPbX 3 hybrid perovskite nanoparticles (NPs) is presented, where MA = Methylammonium and X = I, Br and Cl, as well as their mixed halide counterparts. The methodologyp roposedi ss imple and uses low-costc ommercialp recursors. The conventionalm ethodo fh ybrid perovskite preparation requires methylammoniumh alide precursorsa nd highly polar solvents. Mandatory use of polar solvents and ap articular perovskite precursor makes an intermediate compound which then requires an on-polar solvent to recovert he NPs. In contrast here, aw hole range of mixed halide perovskite NPs is fabricated without using a methylammonium halide precursor andapolar solvent. In this method, an on-polar solventi su sed, which provides a better platform for the particler ecovery.O rganicc ations on the nanoparticle surfacep revent degradationf rom water, due to their hydrophobic nature,a nd hence offer as table colloidal suspension in toluenef or more than three months. Ab-initio calculations within density functional theory( DFT) predict lower formation energies compared to previously reportedv alues, confirming better chemical stabilityf or this synthesis pathway.T hrough the halide compositionalt uning, these NPs exhibit av ariety of emission and absorption starting from ultraviolet to near infrared (IR). The absorption spectra of various halide perovskite show as harp band edge over the visible wavelength with high absorption coefficient. High oscillators trengths due to high excitonic binding energies combined with the simulated finite dipole transition probabilities point towards the observed high absorption. The emission spectra of mixed halidep erovskites vary from 400 to 750 nm, which coverst he whole range of visible spectra with sharp full-width at half maxima. Different halide perovskite exhibit average recombination lifetimef rom 5t o 227 ns. Ambients ynthesis, chemical robustness and tunability of emission with varying halide compositions make MAPbX 3 (X = I, Br and Cl) NPs appealing for the optoelectronica pplications.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.