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TAO-DFT Study on the Electronic Properties of Diamond-Shaped Graphene Nanoflakes
At the nanoscale, it has been rather troublesome to properly explore the properties associated with electronic systems exhibiting a radical nature using traditional electronic structure methods. Graphene nanoflakes, which are graphene nanostructures of different shapes and sizes, are typical example...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7353095/ https://www.ncbi.nlm.nih.gov/pubmed/32630573 http://dx.doi.org/10.3390/nano10061236 |
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author | Huang, Hong-Jui Seenithurai, Sonai Chai, Jeng-Da |
author_facet | Huang, Hong-Jui Seenithurai, Sonai Chai, Jeng-Da |
author_sort | Huang, Hong-Jui |
collection | PubMed |
description | At the nanoscale, it has been rather troublesome to properly explore the properties associated with electronic systems exhibiting a radical nature using traditional electronic structure methods. Graphene nanoflakes, which are graphene nanostructures of different shapes and sizes, are typical examples. Recently, TAO-DFT (i.e., thermally-assisted-occupation density functional theory) has been formulated to tackle such challenging problems. As a result, we adopt TAO-DFT to explore the electronic properties associated with diamond-shaped graphene nanoflakes with n = 2–15 benzenoid rings fused together at each side, designated as n-pyrenes (as they could be expanded from pyrene). For all the n values considered, n-pyrenes are ground-state singlets. With increasing the size of n-pyrene, the singlet-triplet energy gap, vertical ionization potential, and fundamental gap monotonically decrease, while the vertical electron affinity and symmetrized von Neumann entropy (which is a quantitative measure of radical nature) monotonically increase. When n increases, there is a smooth transition from the nonradical character of the smaller n-pyrenes to the increasing polyradical nature of the larger n-pyrenes. Furthermore, the latter is shown to be related to the increasing concentration of active orbitals on the zigzag edges of the larger n-pyrenes. |
format | Online Article Text |
id | pubmed-7353095 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-73530952020-07-15 TAO-DFT Study on the Electronic Properties of Diamond-Shaped Graphene Nanoflakes Huang, Hong-Jui Seenithurai, Sonai Chai, Jeng-Da Nanomaterials (Basel) Article At the nanoscale, it has been rather troublesome to properly explore the properties associated with electronic systems exhibiting a radical nature using traditional electronic structure methods. Graphene nanoflakes, which are graphene nanostructures of different shapes and sizes, are typical examples. Recently, TAO-DFT (i.e., thermally-assisted-occupation density functional theory) has been formulated to tackle such challenging problems. As a result, we adopt TAO-DFT to explore the electronic properties associated with diamond-shaped graphene nanoflakes with n = 2–15 benzenoid rings fused together at each side, designated as n-pyrenes (as they could be expanded from pyrene). For all the n values considered, n-pyrenes are ground-state singlets. With increasing the size of n-pyrene, the singlet-triplet energy gap, vertical ionization potential, and fundamental gap monotonically decrease, while the vertical electron affinity and symmetrized von Neumann entropy (which is a quantitative measure of radical nature) monotonically increase. When n increases, there is a smooth transition from the nonradical character of the smaller n-pyrenes to the increasing polyradical nature of the larger n-pyrenes. Furthermore, the latter is shown to be related to the increasing concentration of active orbitals on the zigzag edges of the larger n-pyrenes. MDPI 2020-06-25 /pmc/articles/PMC7353095/ /pubmed/32630573 http://dx.doi.org/10.3390/nano10061236 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Huang, Hong-Jui Seenithurai, Sonai Chai, Jeng-Da TAO-DFT Study on the Electronic Properties of Diamond-Shaped Graphene Nanoflakes |
title | TAO-DFT Study on the Electronic Properties of Diamond-Shaped Graphene Nanoflakes |
title_full | TAO-DFT Study on the Electronic Properties of Diamond-Shaped Graphene Nanoflakes |
title_fullStr | TAO-DFT Study on the Electronic Properties of Diamond-Shaped Graphene Nanoflakes |
title_full_unstemmed | TAO-DFT Study on the Electronic Properties of Diamond-Shaped Graphene Nanoflakes |
title_short | TAO-DFT Study on the Electronic Properties of Diamond-Shaped Graphene Nanoflakes |
title_sort | tao-dft study on the electronic properties of diamond-shaped graphene nanoflakes |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7353095/ https://www.ncbi.nlm.nih.gov/pubmed/32630573 http://dx.doi.org/10.3390/nano10061236 |
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