Integrated Genomic Selection for Accelerating Breeding Programs of Climate-Smart Cereals.

Rapidly rising population and climate changes are two critical issues that require immediate action to achieve sustainable development goals. The rising population is posing increased demand for food, thereby pushing for an acceleration in agricultural production. Furthermore, increased anthropogenic activities have resulted in environmental pollution such as water pollution and soil degradation as well as alterations in the composition and concentration of environmental gases. These changes are affecting not only biodiversity loss but also affecting the physio-biochemical processes of crop plants, resulting in a stress-induced decline in crop yield. To overcome such problems and ensure the supply of food material, consistent efforts are being made to develop strategies and techniques to increase crop yield and to enhance tolerance toward climate-induced stress. Plant breeding evolved after domestication and initially remained dependent on phenotype-based selection for crop improvement. But it has grown through cytological and biochemical methods, and the newer contemporary methods are based on DNA-marker-based strategies that help in the selection of agronomically useful traits. These are now supported by high-end molecular biology tools like PCR, high-throughput genotyping and phenotyping, data from crop morpho-physiology, statistical tools, bioinformatics, and machine learning. After establishing its worth in animal breeding, genomic selection (GS), an improved variant of marker-assisted selection (MAS), has made its way into crop-breeding programs as a powerful selection tool. To develop novel breeding programs as well as innovative marker-based models for genetic evaluation, GS makes use of molecular genetic markers. GS can amend complex traits like yield as well as shorten the breeding period, making it advantageous over pedigree breeding and marker-assisted selection (MAS). It reduces the time and resources that are required for plant breeding while allowing for an increased genetic gain of complex attributes. It has been taken to new heights by integrating innovative and advanced technologies such as speed breeding, machine learning, and environmental/weather data to further harness the GS potential, an approach known as integrated genomic selection (IGS). This review highlights the IGS strategies, procedures, integrated approaches, and associated emerging issues, with a special emphasis on cereal crops. In this domain, efforts have been taken to highlight the potential of this cutting-edge innovation to develop climate-smart crops that can endure abiotic stresses with the motive of keeping production and quality at par with the global food demand.

Thermodynamics and Kinetics of the Cathode-Electrolyte Interface in All-Solid-State Li-S Batteries.

Lithium-sulfur batteries (LSBs) are among the most promising energy storage technologies due to the low cost and high abundance of S. However, the issue of polysulfide shuttling with its corresponding capacity fading is a major impediment to its commercialization. Replacing traditional liquid electrolytes with solid-state electrolytes (SEs) is a potential solution. Here, we present a comprehensive study of the thermodynamics and kinetics of the cathode-electrolyte interface in all-solid-state LSBs using density functional theory based calculations and a machine learning interatomic potential. We find that among the major solid electrolyte chemistries (oxides, sulfides, nitrides, and halides), sulfide SEs are generally predicted to be the most stable against the S8 cathode, while the other SE chemistries are predicted to be highly electrochemically unstable. If the use of other SE chemistries is desired for other reasons, several binary and ternary sulfides (e.g., LiAlS2, Sc2S3, Y2S3) are predicted to be excellent buffer layers. Finally, an accurate moment tensor potential to study the S8|ß-Li3PS4 interface was developed using an active learning approach. Molecular dynamics (MD) simulations of large interface models (>1000s atoms) revealed that the most stable Li3PS4(100) surface tends to form interfaces with S8 with 2D channels and lower activation barriers for Li diffusion. These results provide critical new insights into the cathode-electrolyte interface design for next-generation all-solid-state LSBs.

A stable cathode-solid electrolyte composite for high-voltage, long-cycle-life solid-state sodium-ion batteries.

Rechargeable solid-state sodium-ion batteries (SSSBs) hold great promise for safer and more energy-dense energy storage. However, the poor electrochemical stability between current sulfide-based solid electrolytes and high-voltage oxide cathodes has limited their long-term cycling performance and practicality. Here, we report the discovery of the ion conductor Na3-xY1-xZrxCl6 (NYZC) that is both electrochemically stable (up to 3.8 V vs. Na/Na+) and chemically compatible with oxide cathodes. Its high ionic conductivity of 6.6 × 10-5 S cm-1 at ambient temperature, several orders of magnitude higher than oxide coatings, is attributed to abundant Na vacancies and cooperative MCl6 rotation, resulting in an extremely low interfacial impedance. A SSSB comprising a NaCrO2 + NYZC composite cathode, Na3PS4 electrolyte, and Na-Sn anode exhibits an exceptional first-cycle Coulombic efficiency of 97.1% at room temperature and can cycle over 1000 cycles with 89.3% capacity retention at 40 °C. These findings highlight the immense potential of halides for SSSB applications.

Effect of conjugation on the vibrational modes of a carbon nanotube dimer.

First Principles simulation studies using the density functional theory have been performed to investigate the effect of conjugation on vibrational modes when two CNTs of different chiralities are held together to constitute an inhomogeneous dimer. Raman Spectra of a (5, 0) CNT; a (6,0) CNT and a (5,0)- (6,0) CNT dimer comprising of parallel standing (5,0) and (6,0) CNTs held by weak Van der Waals were simulated. Various vibrational modes in different frequency regions have been discussed in detail. A red shift is observed overall that clearly affirms the stability and existence of the structure formed by conjugation of CNTs. In the RBM (Radial Breathing Mode) region, additional peaks can be seen arising out of the coupled vibrations. D-band peaks of the dimer cover the D-band peaks of both the CNTs as disorder in the constituents reflects in its constitution. In the G-band region of the dimer spectrum, a low wavelength component with Lorentzian shape and a weak high wavelength component with a Breit Wigner Fano (BWF) kind of line-shape suggest metallic nature of the inhomogeneous CNT dimer.

Rechargeable Alkali-Ion Battery Materials: Theory and Computation.

Since its development in the 1970s, the rechargeable alkali-ion battery has proven to be a truly transformative technology, providing portable energy storage for devices ranging from small portable electronics to sizable electric vehicles. Here, we present a review of modern theoretical and computational approaches to the study and design of rechargeable alkali-ion battery materials. Starting from fundamental thermodynamics and kinetics phenomenological equations, we rigorously derive the theoretical relationships for key battery properties, such as voltage, capacity, alkali diffusivity, and other electrochemically relevant computable quantities. We then present an overview of computational techniques for the study of rechargeable alkali-ion battery materials, followed by a critical review of the literature applying these techniques to yield crucial insights into battery operation and performance. Finally, we provide perspectives on outstanding challenges and opportunities in the theory and computation of rechargeable alkali-ion battery materials.

The effects of interstitial iodine in hybrid perovskite hot carrier cooling: A non-adiabatic molecular dynamics study.

Understanding the defect chemistry of lead-halide perovskites and its effects on the hot-carrier lifetime is of significance for both fundamental understanding and applications as solar cell light absorbing materials. In this study, the mechanistic details of hot carrier decay in hybrid perovskites are investigated using a newly developed non-adiabatic molecular dynamics method. In this approach, the nuclear trajectory is based on Born-Oppenheimer ground state molecular dynamics, which is then followed by the evolution of carrier wave function including the detailed balance and decoherence effects. We found the longer decay time for hot electrons due to the incorporation of interstitial iodine in the hybrid lead-halide perovskites (MAPbI3), while the hot hole decay time is not affected significantly by the interstitial iodine. The underlying mechanism for such modulation of hot carrier dynamics is attributed to the changes of carrier density of states and the electron-phonon coupling strength. Hence, iodine interstitial is the necessary condition to create long-lived hot electrons in perovskites, which is further demonstrated by the comparative analysis with the pure MAPbI3.

Designing a porous-crystalline structure of ß-Ga2O3: a potential approach to tune its opto-electronic properties.

ß-Ga2O3 has drawn recent attention as a state-of-the-art electronic material due to its stability, optical transparency and appealing performance in power devices. However, it has also found a wider range of opto-electronic applications including photocatalysis, especially in its porous form. For such applications, a lower band gap must be obtained and an electron-hole spatial separation would be beneficial. Like many other metal oxides (e.g. Al2O3), Ga2O3 can also form various types of porous structure. In the present study, we investigate how its optical and electronic properties can be changed in a particular porous structure with stoichiometrically balanced and extended vacancy channels. We apply a set of first principles computational methods to investigate the formation and the structural, dynamic, and opto-electronic properties. We find that such an extended vacancy channel is mechanically stable and has relatively low formation energy. We also find that this results in a spatial separation of the electron and hole, forming a long-lived charge transfer state that has desirable characteristics for a photocatalyst. In addition, the electronic band gap reduces to the vis-region unlike the transparency in the pure ß-Ga2O3 crystal. Thus, our systematic study is promising for the application of such a porous structure of ß-Ga2O3 as a versatile electronic material.

Regulation of transport properties by polytypism: a computational study on bilayer MoS2.

Being a member of the van der Waals class of solids, bilayer MoS2 exhibits polytypism due to different possible stacking arrangements, namely, 2Hc, 2Ha and 3R-polytypes. Unlike monolayer MoS2, these bilayers exhibit indirect band gaps. Band extrema states originate from a linear combination of Mo-(d) and S-(p) orbitals which are sensitive to the interlayer interactions. We have studied the impact of stacking pattern on the electronic structure and electron/hole transport properties of these polytypes. Based on first-principles computations coupled with the Boltzmann transport formalism, we found that a strong electron-hole anisotropy can be realised in the 2Ha-MoS2 polytype unlike in a monolayer which is isotropic in nature. A staggered arrangement between two layers results in a higher relaxation time for electrons compared to holes leading to anisotropy which is of importance in device engineering.

Anodic performance of black phosphorus in magnesium-ion batteries: the significance of Mg-P bond-synergy.

By means of first-principles analysis, we have shown that black phosphorus shows promise as a low potential and high capacity anode in Mg-ion batteries. The fact that deserves the most attention is synergistic interaction between Mg-ions and the covalent P-host that reduces the Mg-diffusion barrier and optimizes the anodic voltage, thereby can overcome the bottleneck in Mg-battery machinery.

Origin of the Order-Disorder Transition and the Associated Anomalous Change of Thermopower in AgBiS2 Nanocrystals: A Combined Experimental and Theoretical Study.

Bulk AgBiS2 crystallizes in a trigonal crystal structure (space group, P3̅m1) at room temperature, which transforms to a cation disordered rock salt structure (space group, Fm3̅m) at ∼473 K. Surprisingly, at room temperature, a solution-grown nanocrystal of AgBiS2 crystallizes in a metastable Ag/Bi ordered cubic structure, which transforms to a thermodynamically stable disorded cubic structure at 610 K. Moreover, the order-disorder transition in nanocrystalline AgBiS2 is associated with an unusual change in thermopower. Here, we shed light on the origin of a order-disorder phase transition and the associated anomalous change of thermopower in AgBiS2 nanocrystals by using a combined experimental, density functional theory based first-principles calculation and ab initio molecular dynamics simulations. Positron-annilation spectroscopy indicates the presence of higher numbers of Ag vacancies in the nanocrystal compared to that of the bulk cubic counterpart at room temperature. Furthermore, temperature-dependent two-detector coincidence Doppler broadening spectroscopy and Doppler broadening of the annihilation radiation (S parameter) indicate that the Ag vacancy concentration increases abruptly during the order-disorder transition in nanocrystalline AgBiS2. At high temperature, a Ag atom shuttles between the vacancy and interstitial sites to form a locally disordered cation sublattice in the nanocrystal, which is facilitated by the formation of more Ag vacancies during the phase transition. This process increases the entropy of the system at higher vacancy concentration, which, in turn, results in the unusual rise in thermopower.

Charge-transport anisotropy in black phosphorus: critical dependence on the number of layers.

Phosphorene is a promising candidate for modern electronics because of the anisotropy associated with high electron-hole mobility. Additionally, superior mechanical flexibility allows the strain-engineering of various properties including the transport of charge carriers in phosphorene. In this work, we have shown the criticality of the number of layers to dictate the transport properties of black phosphorus. Trilayer black phosphorus (TBP) has been proposed as an excellent anisotropic material, based on the transport parameters using Boltzmann transport formalisms coupled with density functional theory. The mobilities of both the electron and the hole are found to be higher along the zigzag direction (∼10(4) cm(2) V(-1) s(-1) at 300 K) compared to the armchair direction (∼10(2) cm(2) V(-1) s(-1)), resulting in the intrinsic directional anisotropy. Application of strain leads to additional electron-hole anisotropy with 10(3) fold higher mobility for the electron compared to the hole. Critical strain for maximum anisotropic response has also been determined. Whether the transport anisotropy is due to the spatial or charge-carrier has been determined through analyses of the scattering process of electrons and holes, and their recombination as well as relaxation dynamics. In this context, we have derived two descriptors (S and F(k)), which are general enough for any 2D or quasi-2D systems. Information on the scattering involving purely the carrier states also helps to understand the layer-dependent photoluminescence and electron (hole) relaxation in black phosphorus. Finally, we justify trilayer black phosphorus (TBP) as the material of interest with excellent transport properties.

Eu3Ir2In15: A Mixed-Valent and Vacancy-Filled Variant of the Sc5Co4Si10 Structure Type with Anomalous Magnetic Properties.

A new compound, Eu3Ir2In15, has been synthesized using indium as an active metal flux. The compound crystallizes in the tetragonal P4/mbm space group with lattice parameters a = 14.8580(4) Å, b = 14.8580(4) Å, and c = 4.3901(2) Å. It was further characterized by SEM-EDX studies. The effective magnetic moment (µeff) of this compound is 7.35 µB/Eu ion with a paramagnetic Curie temperature (θp) of -28 K, suggesting antiferromagnetic interaction. The mixed-valent nature of Eu observed in magnetic measurements was confirmed by XANES measurements. The compound undergoes demagnetization at a low magnetic field (10 Oe), which is quite unusual for Eu-based intermetallic compounds. Temperature-dependent resistivity studies reveal that the compound is metallic in nature. A comparative study was made between Eu3Ir2In15 and hypothetical vacancy-variant Eu5Ir4In10, which also crystallizes in the same crystal structure. However, our computational studies along with control experiments suggest that the latter is thermodynamically less feasible compared to the former, and hence we propose that it is highly unlikely that an RE5T4X10 would exist with X as a group 13 element.

Surface-Mediated Extraction and Photoresponse Modulation of Bisphenol A Derivatives: A Computational Study.

2,2'-bis(4-hydroxyphenyl) propane (BPA) and its metabolites 4-methyl-2,4-bis(p-hydroxyphenyl)pent-2-ene (M-1) and 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (M-2) are common in drinking water and hard plastics and thus pose serious health hazards. These are also known as endocrine disrupting chemicals (EDCs). In this paper, we discuss the surface-mediated adsorption mechanism and subsequent changes in the electronic structure of EDCs. This is in view of their separation from environment and possible photodecomposition. Computational investigation based on density functional theory and ab initio molecular dynamics was performed on bisphenol compounds (BPA, M-1, and M-2) as guest and affinity-based separation media as substrate. Static properties (at 0 K) and conformational dynamics upon physisorption (at T = 300 K) depict the potential of 2H-MoS2 surface for reversible adsorption/desorption and selective isolation of these EDCs. In contrast, layered graphene supports very strong surface adsorption and assures complete removal of EDCs. In particular, optical response of the EDCs gets tuned upon surface adsorption. Hence, understanding the surface adsorption and modulation of the electronic structure would reveal possible means for extraction and photodegradation of a major class of environmental pollutants by specific choice of surface.

Criticality of surface topology for charge-carrier transport characteristics in two-dimensional borocarbonitrides: design principles for an efficient electronic material.

We have studied the effect of the spatial distribution of B, N and C domains in 2-dimensional borocarbonitrides and its influence on carrier mobility, based on density functional theory coupled with the Boltzmann transport equation. Two extreme features of C-domains in BN-rich B2.5CN2.5, namely, BCN-I (random) and BCN-II (localized), have been found to exhibit an electron (hole) mobility of ∼10(6) cm(2) V(-1) s(-1) (∼10(4) cm(2) V(-1) s(-1)) and ∼10(3) cm(2) V(-1) s(-1) (∼10(6) cm(2) V(-1) s(-1)), respectively. We have ascertained the underlying microscopic mechanisms behind such an extraordinarily large carrier mobility and the reversal of conduction polarity. Finally, we have derived the principle underlying the maximization of mobility and for obtaining a particular (electron/hole) conduction polarity of this nanohybrid in any stoichiometric proportion.

Formation mechanism and possible stereocontrol of bisphenol a derivatives: a computational study.

Density functional theoretical study elucidates two different pathways for metabolic activation of 2,2'-bis(4-hydroxyphenyl) propane (Bisphenol A; BPA) and consequential formation of 4-methyl-2,4-bis(p-hydroxyphenyl)pent-2-ene (M-1) and 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (M-2, the potential environmental estrogen). Selectivity toward M-1(nontoxic)/M-2(toxic) formation can be controlled by varying the polarity of the reaction medium. We also found the reversal of thermodynamic stability for M-1/M-2 in response to the static polarization of the medium. Moreover, stereocontrol of biologically active M-2 with static polarization as the switch (∼0.005 au) might affect the receptor binding. This analysis may be useful in dictating the prevention of the harmful action of BPA and its metabolites.

Density functional theoretical investigation on structure, optical response and hydrogen adsorption properties of B9/metal-B9 clusters.

DFT calculations have been carried out to shed light on the electronic structure, optical properties and hydrogen adsorption capability of neutral MB9 (where M = Li3, Na3, K3, Al, Ga, In, Rh and Co) clusters. Electronic structural studies on the parent B9(3-) clusters reveal that a less aromatic hypervalent B-centred B8 ring geometry is energetically more favoured. However, GM(3+) (Al, Ga and In) in GM@B9 prefers a highly aromatic metal-centred 9-membered molecular wheel structure. In addition, the larger size of indium breaks the D9h symmetry of the molecular wheel by coming slightly out of the ring plane unlike Al@B9 and Ga@B9. B9(n-) (n = 1-3) is also neutralized with 'n' number of Li, Na and K which revealed that AM2B9 and AM2B9(-) result in pyramidal geometries while AM3B9 results in an irregular shape by retaining the B9 framework similar to the most stable conformer of B9(3-). Metal@B9 molecular wheels show optical absorption in a broad range of the spectrum (from UV to NIR: 260-1000 nm), which is attributed to the metal's ability to perturb the ring centred excited state. Ga@B9 and Co@B9 bind with hydrogen molecules in a dissociative manner, forming two covalent bonds with peripheral B atoms of the B9 ring.