2022 New's Items

Improving machine learning performance on small chemical reaction data with unsupervised contrastive pretraining

Wen M
Blau SM
Xie X
Dwaraknath S
Persson KA
2022

Machine learning (ML) methods have great potential to transform chemical discovery by accelerating the exploration of chemical space and drawing scientific insights from data. However, modern chemical reaction ML models, such as those based on graph neural networks (GNNs), must be trained on a large amount of labelled data in order to avoid overfitting the data and thus possessing low accuracy and transferability. In this work, we propose a strategy to leverage unlabelled data to learn accurate ML models for small labelled chemical reaction data. We focus on an old and prominent...

Tuning the Solvation Structure in Aqueous Zinc Batteries to Maximize Zn-Ion Intercalation and Optimize Dendrite-Free Zinc Plating

Li C
Kingsbury R
Zhou L
Shyamsunder A
Persson KA
Nazar LF
2022

Aqueous zinc batteries are recognized to suffer from H+/Zn2+ coinsertion in the cathode, but few approaches have been reported to suppress deleterious H+ intercalation. Herein, we realize this goal by tuning the solvation structure, using LiV2(PO4)3 (LVP) as a model cathode. Phase conversion of LVP induced by H+ intercalation is observed in 4 m Zn(OTf)2, whereas...

Performance comparison of r 2 SCAN and SCAN metaGGA density functionals for solid materials via an automated, high-throughput computational workflow

Kingsbury R
Gupta AS
Bartel CJ
Munro JM
Dwaraknath S
Horton M
Persson KA
2022

Computational materials discovery efforts utilize hundreds or thousands of density functional theory calculations to predict material properties. Historically, such efforts have performed calculations at the generalized gradient approximation (GGA) level of theory due to its efficient compromise between accuracy and computational reliability. However, high-throughput calculations at the higher metaGGA level of theory are becoming feasible. The strongly constrained and appropriately normed (SCAN) metaGGA functional offers superior accuracy to GGA across much of chemical space, making...

An assessment of density functionals for predicting CO2 adsorption in diamine-functionalized metal–organic frameworks

Lee JH
Hyldgaard P
Neaton JB
2022

Diamine-functionalized M2(dobpdc) (M = Mg, Mn, Fe, Co, Zn) metal–organic frameworks (MOFs) are among a growing class of crystalline solids currently being intensively investigated for carbon capture as they exhibit a novel cooperative and selective CO2 adsorption mechanism and a step-shaped isotherm. To understand their CO2 adsorption behavior, ab initio calculations with near-chemical accuracy (∼6 kJ/mol, an average experimental error) are required. Here, we present density functional theory (...

Screening of Excitons by Organic Cations in Quasi-Two-Dimensional Organic–Inorganic Lead-Halide Perovskites

Filip MR
Qiu DY
Del Ben M
Neaton JB
2022

Interlayer organic cations in quasi-two-dimensional halide perovskites are a versatile tuning vehicle for the optoelectronic properties of these complex systems, but chemical intuition for this design route is yet to be established. Here, we use density functional theory, the GW approximation, and the Bethe-Salpeter equation approach to understand the contribution of the organic cation to the quasiparticle band gap and exciton binding energy of layered perovskites. We show that organic cations in quasi-two-dimensional perovskites contribute significantly to the...

An optimally tuned range-separated hybrid starting point for ab initio GW plus Bethe–Salpeter equation calculations of molecules

McKeon CA
Hamed SM
Bruneval F
Neaton JB
2022

The ab initio GW plus Bethe–Salpeter equation (GW-BSE, where G is the one particle Green's function and W is the screened Coulomb interaction) approach has emerged as a leading method for predicting excitations in both solids and molecules with a predictive power contingent upon several factors. Among these factors are the (1) generalized Kohn–Sham eigensystem used to construct the GW self-energy and to solve the BSE and (2) the efficacy and suitability of the Tamm–Dancoff approximation. Here, we present a detailed benchmark study of low-lying singlet excitations from a...

Addressing solar photochemistry durability with an amorphous nickel antimonate photoanode

Zhou L
Peterson EA
Rao KK
Lu Y
Yano J
Neaton JB
Bajdich M
Gregoire JM
2022

Renewable generation of fuels using solar energy is a promising technology whose deployment hinges on the discovery of materials with a combination of durability and solar...

Electronic structure of strain-tunable Janus WSSe–ZnO heterostructures from first-principles

Peterson EA
Debela TT
Gomoro GM
Neaton JB
Asres GA
2022

The electronic structure of semiconducting 2D materials such as monolayer transition metal dichalcogenides (TMDs) are known to be tunable via environment and external fields, and van der Waals (vdW) heterostructures consisting of stacks of distinct types of 2D materials offer the possibility to further tune and optimize the electronic properties of 2D materials. In this work, we use density functional theory (DFT) calculations to calculate the structure and electronic properties of a vdW heterostructure of Janus monolayer WSSe with monolayer ZnO, both of...

Fe Substitutions Improve Spectral Response of Bi2WO6-Based Photoanodes

Zhou L
Peterson EA
Richter MH
Richter MH
Lai Y
Gregoire JM
Neaton JB
2022

The quest for a scalable solar fuel technology has stimulated a concerted effort to develop a metal oxide semiconductor for solar-driven photoelectrochemical water oxidation (oxygen evolution reaction) in an efficient and durable manner. So far, the search for such a metal oxide photoanode has highlighted the promise of Bi-based oxides, which have also been extensively studied for other photocatalyst applications. Bi2WO6 is a durable photocatalyst whose primary shortcoming is a 2.8 eV band gap that limits utilization of the solar...

From an antiferromagnetic insulator to a strongly correlated metal in square-lattice MCl2(pyrazine)2 coordination solids

Perlepe P
Oyarzabal I
Voigt L
Kubus M
Pedersen KS
Vignolle B
Mathoniere C
Long JR
Neaton JB
Clerac R
2022

Electronic synergy between metal ions and organic linkers is a key to engineering molecule-based materials with a high electrical conductivity and, ultimately, metallicity. To enhance conductivity in metal-organic solids, chemists aim to bring the electrochemical potentials of the constituent metal ions and bridging organic ligands closer in a quest to obtain metal-d and ligand-π admixed frontier bands. Herein, we demonstrate the critical role of the metal ion in tuning the electronic ground state of such materials. While VCl2(...