Banca de DEFESA: LEONARDO DE SOUZA BARBOSA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LEONARDO DE SOUZA BARBOSA
DATE: 27/09/2023
TIME: 14:00
LOCAL: Auditório da Física
TITLE:

Viability of inorganic nanobelts: a study on their electronic, optical and thermodynamic properties.

KEY WORDS:

BN-Nanobelt, SiC-Nanobelt, Electronic, Optics, Thermodynamic, DFT.

PAGES: 82
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

In recent years, organic molecules known as carbon nanobelts have been the subject of much research. Recently, one of these molecules - called (12)cyclophenacene - was synthesized. This synthesis marked a great advance in synthesis technologies since this molecule has been studied since the 1950s. In this work, two new molecules derived from (12)cyclophenacene are proposed, which are called silicon carbide nanobelt or SiC-nanobelt (C24Si24H24) and boron nitride nanobelt or BN-nanobelt (B24N24H24). To verify stability and possible applications of these molecules, the electronic, optical, and thermodynamic properties of SiC and BN-nanobelts were determined. These properties were calculated using the DFT method with the PWC and PBE functionals, with the Double Numerical Plus Polarization (DNP) basis set. It was verified, through electronic structure calculations, that the BN-nanobelt is more stable (-14.11 hartrees) than the SiC-nanobelt (-12.21 hartrees). It was also observed that the SiC-nanobelt has characteristics of a semiconductor (GAP estimated at 2.13 eV), and the BN-nanobelt has characteristics of an insulator (GAP estimated at 4.62 eV). Optical properties revealed that SiC-nanobelt absorbs in the visible region, while BNnanobelt absorbs in the ultraviolet region. From the point of view of thermodynamic properties, it was observed through the Gibbs free energy that for a temperature above 718 K a spontaneous reaction occurs for SiC-nanobelt. Furthermore, quantum dynamics calculations showed that both proposed nanobelts are thermally stable, with the bonds of BN-nanobelt and SiC-nanobelt breaking at temperatures of 3000 K and 2500 K respectively. Based on the results obtained for the electronic, optical, thermodynamic, and dynamic properties, it is possible to infer that the new inorganic nanobelts are stable systems (their syntheses are viable) and have potential technological applications

COMMITTEE MEMBERS:
Interno - 3272139 - ALEXANDRE CAVALHEIRO DIAS
Presidente - 407633 - DAVID LIMA AZEVEDO
Externo à Instituição - EDVAN MOREIRA - UEMA
Externo à Instituição - NILTON FERREIRA FRAZÃO - UFCG
Interno - 1273560 - RICARDO GARGANO