TY - JOUR
T1 - Organic Higher-Order Topological Insulators
T2 - Heterotriangulene-Based Covalent Organic Frameworks
AU - Ni, Xiaojuan
AU - Huang, Huaqing
AU - Brédas, Jean Luc
N1 - Funding Information:
This work was supported by the College of Science of the University of Arizona. H.H. was supported by the National Key R&D Program of China (No. 2021YFA1401600), the National Natural Science Foundation of China (Grant No. 12074006), and the Start-up Funds from Peking University. The authors gratefully acknowledge the Research Data Center at the University of Arizona for providing high-performance computing resources.
Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.
PY - 2022/12/14
Y1 - 2022/12/14
N2 - The ability to design and control the chemical characteristics of covalent organic frameworks (COFs) offers a new avenue for the development of functional materials, especially with respect to topological properties. Based on density functional theory calculations, by varying the core units through the choice of bridging groups [O, Câ• O, CH2, or C(CH3)2] and the linker units [acetylene, diacetylene, or benzene], we have designed heterotriangulene-based COFs that are predicted to be two-dimensional higher-order topological insulators (TIs). The higher-order TI characteristics of these COFs are identified via their topological invariants and the presence of in-gap topological corner modes and gapped edge states. The frontier molecular orbital energies of the building moieties play an important role in determining the size of the higher-order TI gap, which we find to be highly dependent on linker units. We also examined the deposition of the COFs on a boron nitride substrate to assess the feasibility of experimental observation of a higher-order TI phase in the organic layer. This work thus provides new insights into heterotriangulene-based COFs and guidance for the exploration of purely organic topological materials.
AB - The ability to design and control the chemical characteristics of covalent organic frameworks (COFs) offers a new avenue for the development of functional materials, especially with respect to topological properties. Based on density functional theory calculations, by varying the core units through the choice of bridging groups [O, Câ• O, CH2, or C(CH3)2] and the linker units [acetylene, diacetylene, or benzene], we have designed heterotriangulene-based COFs that are predicted to be two-dimensional higher-order topological insulators (TIs). The higher-order TI characteristics of these COFs are identified via their topological invariants and the presence of in-gap topological corner modes and gapped edge states. The frontier molecular orbital energies of the building moieties play an important role in determining the size of the higher-order TI gap, which we find to be highly dependent on linker units. We also examined the deposition of the COFs on a boron nitride substrate to assess the feasibility of experimental observation of a higher-order TI phase in the organic layer. This work thus provides new insights into heterotriangulene-based COFs and guidance for the exploration of purely organic topological materials.
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U2 - 10.1021/jacs.2c11229
DO - 10.1021/jacs.2c11229
M3 - Article
C2 - 36469524
AN - SCOPUS:85143530334
SN - 0002-7863
VL - 144
SP - 22778
EP - 22786
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 49
ER -