Singlet fission(SF),the conversion of one singlet exciton into two triplet excitons,could significantly enhance solar cell efficiency.Molecular crystals that undergo SF are scarce.Computational exploration may acceler...Singlet fission(SF),the conversion of one singlet exciton into two triplet excitons,could significantly enhance solar cell efficiency.Molecular crystals that undergo SF are scarce.Computational exploration may accelerate the discovery of SF materials.However,many-body perturbation theory(MBPT)calculations of the excitonic properties of molecular crystals are impractical for large-scale materials screening.We use the sure-independence-screening-and-sparsifying-operator(SISSO)machine-learning algorithm to generate computationally efficient models that can predict the MBPT thermodynamic driving force for SF for a dataset of 101 polycyclic aromatic hydrocarbons(PAH101).SISSO generates models by iteratively combining physical primary features.The best models are selected by linear regression with cross-validation.The SISSO models successfully predict the SF driving force with errors below 0.2 eV.Based on the cost,accuracy,and classification performance of SISSO models,we propose a hierarchical materials screening workflow.Three potential SF candidates are found in the PAH101 set.展开更多
Magnetism has revolutionized important technologies,and continues to bring forth new phenomena in emergent materials and reduced dimensions.Here,using first-principles calculations,we demonstrate that the already-synt...Magnetism has revolutionized important technologies,and continues to bring forth new phenomena in emergent materials and reduced dimensions.Here,using first-principles calculations,we demonstrate that the already-synthesized two-dimensional(2D)Ni-tetracyanoquinodimethane(Ni_(2)(TCNQ)_(2))lattice is a stable ferromagnetism material with multiple spin-polarized Dirac cones.The conical bands in proximity of the Fermi level can be tuned by external tensile strain and show the fourfold degenerate electronic states at the critical tensile strain of~2.35%,whose energy dispersion is consistent with 2D Cairo pentagonal lattice.In addition,spin-orbital coupling can open a band gap at the Dirac point of A,leading to topologically nontrivial electronic states characterized by the non-zero Chern number and the edge states of nanoribbon.Our results offer versatile platforms for the realization of massless spintronics with full-spin polarization in 2D Cairo pentagonal Ni_(2)(TCNQ)_(2) Lattice.展开更多
基金Work at CMU was supported by the National Science Foundation(NSF)Division of Materials Research through grant DMR-2021803This research used resources of the Argonne Leadership Computing Facility(ALCF),which is a DOE Office of Science User Facility supported under Contract DE-AC02-06CH11357of the National Energy Research Scientific Computing Center(NERSC),a DOE Office of Science User Facility supported by the Office of Science of the US Department of Energy,under Contract DE-AC02-05CH11231.
文摘Singlet fission(SF),the conversion of one singlet exciton into two triplet excitons,could significantly enhance solar cell efficiency.Molecular crystals that undergo SF are scarce.Computational exploration may accelerate the discovery of SF materials.However,many-body perturbation theory(MBPT)calculations of the excitonic properties of molecular crystals are impractical for large-scale materials screening.We use the sure-independence-screening-and-sparsifying-operator(SISSO)machine-learning algorithm to generate computationally efficient models that can predict the MBPT thermodynamic driving force for SF for a dataset of 101 polycyclic aromatic hydrocarbons(PAH101).SISSO generates models by iteratively combining physical primary features.The best models are selected by linear regression with cross-validation.The SISSO models successfully predict the SF driving force with errors below 0.2 eV.Based on the cost,accuracy,and classification performance of SISSO models,we propose a hierarchical materials screening workflow.Three potential SF candidates are found in the PAH101 set.
基金A.W.greatly appreciates the National Natural Science Foundation of China(No.11904131)the Natural Science Foundation of Shandong Province(No.ZR2019BA006)+2 种基金M.Z.thanks the supports from the National Natural Science Foundation of China(No.11774201)the Taishan scholarship of Shandong Province.N.R.appreciates the National Natural Science Foundation of China(No.51972148)L.D.thanks the support from the National Natural Science Foundation of China(No.51802118).
文摘Magnetism has revolutionized important technologies,and continues to bring forth new phenomena in emergent materials and reduced dimensions.Here,using first-principles calculations,we demonstrate that the already-synthesized two-dimensional(2D)Ni-tetracyanoquinodimethane(Ni_(2)(TCNQ)_(2))lattice is a stable ferromagnetism material with multiple spin-polarized Dirac cones.The conical bands in proximity of the Fermi level can be tuned by external tensile strain and show the fourfold degenerate electronic states at the critical tensile strain of~2.35%,whose energy dispersion is consistent with 2D Cairo pentagonal lattice.In addition,spin-orbital coupling can open a band gap at the Dirac point of A,leading to topologically nontrivial electronic states characterized by the non-zero Chern number and the edge states of nanoribbon.Our results offer versatile platforms for the realization of massless spintronics with full-spin polarization in 2D Cairo pentagonal Ni_(2)(TCNQ)_(2) Lattice.
