Cargando…

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...

Descripción completa

Detalles Bibliográficos
Autores principales: Huang, Hong-Jui, Seenithurai, Sonai, Chai, Jeng-Da
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
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
_version_ 1783557795097870336
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
work_keys_str_mv AT huanghongjui taodftstudyontheelectronicpropertiesofdiamondshapedgraphenenanoflakes
AT seenithuraisonai taodftstudyontheelectronicpropertiesofdiamondshapedgraphenenanoflakes
AT chaijengda taodftstudyontheelectronicpropertiesofdiamondshapedgraphenenanoflakes