Molecular Origin of Charge Traps in Polyfluorene-Based Semiconductors

Autor(es)

Faria, Gregorio C. ^{[1, 2]} ; deAzevedo, Eduardo R. ^[1] ; von Seggern, Heinz ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[2] Tech Univ Darmstadt, Inst Mat Sci, D-64287 Darmstadt - Germany

• Tipo de documento: Artigo Científico
• Fonte: MACROMOLECULES; v. 46, n. 19, p. 7865-7873, OCT 8 2013.
• Citações Web of Science: 10

Resumo

The comprehensive control of morphology and structure is of extreme importance in semiconducting polymers when used as active layers in optoelectronic devices. In the work reported here, a systematic investigation of the structural and dynamical properties of poly(9,9-di-n-octyl-fluorene-alt-benzothiadiazole), known as F8BT, and their correlation with electrical properties is presented when the material is used as an active layer in optoelectronic devices. By means of X-ray diffraction, one observes that in thick layer films (thickness of about 4 pm) grown by drop-cast deposition, a solvent induced crystalline phase exists which evolves to a stable phase as the temperature is raised. This was not observed in thin films (thickness of about 250 nm) prepared by spin-coating within the investigated temperature range. By modeling the current-voltages characteristics of both thick and thin film devices, important information on the influence of crystallization on the trapping states could be drawn. Furthermore, the temperature dependence of the charge carrier mobility was found to be closely related to that of the molecular relaxation processes. The understanding of the nature of such molecular relaxations, measured by solid-state nuclear magnetic resonance methods, allows one to understand the importance of molecular relaxations and microstructure changes on the trap states of the system. (AU)

• Processo FAPESP: 07/08688-0 - Dispositivos eletrônicos e optoeletrônicos poliméricos
• Beneficiário: Roberto Mendonça Faria
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 09/18354-8 - Dinâmica e estrutura de sistemas poliméricos estudados por ressonância magnética nuclear
• Beneficiário: Eduardo Ribeiro de Azevedo
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 08/01935-5 - Correlação das propriedades óticas e elétricas com a estrutura física e dinâmica molecular de filmes e dispositivos orgânicos de polifluorenos e derivados
• Beneficiário: Gregório Couto Faria
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 12/01303-4 - Caracterização da morfologia e estrutura molecular em filmes de polímeros conjugados para aplicações em dispositivos fotovoltaicos de alta performance
• Beneficiário: Gregório Couto Faria
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado