title: Structural dependence of MEH-PPV chromism in solution.
abstract: The chromism observed in the MEH-PPV polymer in tetrahydrofuran (THF) solution is discussed as a function of the structural morphology of the backbone chains. To evaluate this phenomenon, we carried out simulations employing a hybrid methodology using molecular dynamics and quantum mechanical approaches. Our results support the hypothesis that the morphological order-disorder transition is related to the change from red to blue phase observed experimentally. The morphological disorder is associated with total or partial twisted arrangements in the polymer backbone, which induces an electronic conjugation length more confined to shorter segments. In addition, the main band of the MEH-PPV UV-Vis spectrum at the lower wavelength is related to the blue phase, in contrast to the red phase found for the more planar backbone chains.
authors.affiliation: Laboratório de Simulação Molecular de Materiais, Departamento de Física, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, CEP 35400-000 Ouro, Preto-MG, Brazil.
authors.forename: Carlos E T
authors.initials: CE
authors.lastname: de Magalhães
authors.affiliation: Laboratório de Simulação Molecular de Materiais, Departamento de Física, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, CEP 35400-000 Ouro, Preto-MG, Brazil.|Laboratório de Polímeros e Propriedades Eletrônicas de Materiais, Departamento de Física, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, 35400-000, Ouro Preto-MG, Brazil.
authors.forename: Ranylson M L
authors.initials: RM
authors.lastname: Savedra
authors.affiliation: Laboratório de Simulação Molecular de Materiais, Departamento de Física, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, CEP 35400-000 Ouro, Preto-MG, Brazil.
authors.forename: Karina S
authors.initials: KS
authors.lastname: Dias
authors.affiliation: Instituto de Física, Universidade de São Paulo, Rua do Matão s/n, trav. R 187, São Paulo-SP, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Ramos
authors.affiliation: Laboratório de Simulação Molecular de Materiais, Departamento de Física, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, CEP 35400-000 Ouro, Preto-MG, Brazil. melissa@iceb.ufop.br.|Laboratório de Polímeros e Propriedades Eletrônicas de Materiais, Departamento de Física, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, 35400-000, Ouro Preto-MG, Brazil. melissa@iceb.ufop.br.
authors.forename: Melissa F
authors.identifier: http://orcid.org/0000-0002-0277-0418
authors.initials: MF
authors.lastname: Siqueira
keywords: Molecular dynamics simulation; Organic electronics; Organic semiconductor; Sequential QM/MM; Spectroscopy