Título:	Dinâmica de pólarons em cristais moleculares orgânicos
Autor(es):	Pereira Júnior, Marcelo Lopes
Orientador(es):	Ribeiro Júnior, Luiz Antônio
Assunto:	Semicondutores orgânicos Transporte de carga Cristais moleculares Dinâmica de pólarons
Data de publicação:	22-Jul-2019
Data de defesa:	20-Fev-2018
Referência:	PEREIRA JÚNIOR, Marcelo Lopes. Dinâmica de pólarons em cristais moleculares orgânicos. 2018. 111 f., il. Dissertação (Mestrado em Ciências de Materiais)–Universidade de Brasília, Brasília, 2018.
Abstract:	The great potential of organic semiconductors for the development of new optoelec- tronic devices with good compromise between cost/performance has increasingly attracted the interest of the scientific community. Applications such as organic light- emitting diodes (OLEDs) and organic photovoltaic cells (OPVs) represent a technologi- cal evolution with low environmental impact, low cost of production and mechanical properties of great relevance (like flexibility and thin thickness). lhe charge transport in organic semiconductors is an important process in the functionality of these devices, so that the stability and the dynamic properties of charge carriers in this materiais are directly linked to the devices performance. The understanding about how it occurs and what are the factors that influence the stability and consequently the dynamics of the charge carriers is a significant challenge in the study of these materiais. In this sense, organic molecular crystals, especially oligoacenes, have shown to be promising materiais in the advance of organic electronics. Organic semiconductors, in their pure State, are insulators and rely on doping processes to become semiconductors. From these doping processes, the formation of charge carriers is induced, being one of the most common: the polaron, where the addition or subtraction of an electron locally polarises the crystal, deforming the lattice where it is, so that the charge and the defor- mations of the lattice are coupled. In this work, the stability and dynamics of polarons in oligoacenes are numerically investigated under influence of externai electric field, anisotropy, disorder and temperature. The main objective of this work is to study the stability and dynamics of polarons in one- and two-dimensional crystals of naphtha- lene, anthracene, pentacene, tetracene, and rubrene. For this study, a semi-empirical approach was used that take into account the intra and intermolecular interactions, named Holstein-Peierls model. The results obtained suggest, among other conclusions, that the polaron has its localization affected depending on the anisotropy degree, but it is still stable. Moreover, it was obtained that the polaron dynamics occurs, according to this model, only in anisotropic Systems, under the influence of externai electric field. The stability also decreases with increasing disorder in the system, which simulates impurities and defects in materiais. The stability of the carrier during the dynamics is also substantially affected with increasing temperature.
Unidade Acadêmica:	Faculdade UnB Planaltina (FUP)
Informações adicionais:	Dissertação (mestrado)–Universidade de Brasília, Faculdade UnB de Planaltina, Programa de Pós-Graduação em Ciências de Materiais, 2018.
Programa de pós-graduação:	Programa de Pós-Graduação em Ciências de Materiais
Licença:	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
DOI:	http://dx.doi.org/10.26512/2018.02.D.35135
Agência financiadora:	Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

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