Magnetic field effects in Alq(3)-based OLEDs investigated by electrical impedance spectroscopy

Autor(es)

Nunes-Neto, Oswaldo ^[1] ; Batagin-Neto, Augusto ^[2] ; Leite, Douglas M. G. ^[3] ; Nuesch, Frank A. ^[4] ; Graeff, Carlos F. O. ^{[1, 5]}

Afiliação do(s) autor(es)

^[1] Univ Estadual Paulista, Fac Ciencias, POSMAT Programa Posgrad Ciencia & Tecnol Mat, UNESP, Bauru - Brazil

^[2] Univ Estadual Paulista, UNESP, Campus Expt Itapeva, Itapeva, SP - Brazil

^[3] Inst Tecnol Aeronaut, Div Ciencias Fundamentais, Dept Fis, Campus CTA, Sao Jose Dos Campos, SP - Brazil

^[4] EMPA, Lab Funct Polymers, Swiss Fed Labs Mat Sci & Technol, Uberlandstr 129, CH-8600 Dubendorf - Switzerland

^[5] Univ Estadual Paulista, Fac Ciencias, UNESP, Bauru - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ORGANIC ELECTRONICS; v. 50, p. 347-358, NOV 2017.
• Citações Web of Science: 4

Resumo

The effect of an external magnetic field on electrical impedance was measured on tris-(8hydroxyquinoline) aluminum (Alq(3)) based OLEDs at different temperatures. Magnetic field effects (MFEs) were responsible for significant changes on the real and imaginary components of the impedance, and for the intensification of the negative capacitance (NC) effect. The observed MFEs do not present a strong temperature dependence. Simulations via equivalent circuits and numerical solutions of Boltzmann transport equations in a drift-diffusion approximation and employing small sinusoidal signal analysis indicate that such effects are consistent with an enhancement of the carrier mobilities and a quenching of the recombination rates. Such changes lead to reduced resistance and more intense NC effects on the device. The results were interpreted in terms of the currently accepted OMAR models: electron-hole pair model, triplet-polaron reaction mechanism and bipolaron model. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 12/03116-7 - Simulação de propriedades ópticas e eletrônicas de materiais orgânicos
• Beneficiário: Augusto Batagin Neto
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 08/57872-1 - Instituto Nacional de Ciências dos Materiais em Nanotecnologia
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 11/21830-6 - Estudo dos Processos de Transporte Dependente de Spin em Células Solares Orgânicas.
• Beneficiário: Oswaldo Nunes Neto
• Modalidade de apoio: Bolsas no Brasil - Doutorado