Fabricação e caracterização estrutural de filmes evaporados de ftalocianinas
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Data
2009-06-26
Autores
Zanfolim, Antonio Aparecido [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Neste trabalho foram preparados filmes finos de ftalocianinas de zinco (ZnPc) e de níquel (NiPc) através da técnica de evaporação térmica à vácuo (PVD - physical vapor deposition) em diversas espessuras e em escala nanométrica com o objetivo de determinar a arquitetura molecular destes filmes bem como suas propriedades ópticas e elétricas. Em última análise buscam-se gerar subsídios para as possíveis aplicações, especialmente dispositivos eletrônicos a base de semicondutores orgânicos e sensores de gás. A ZnPc e a NiPc em pó foram caracterizadas utilizando-se as técnicas de termogravimetria (TG), calorimetria exploratória diferencial (DSC) e os filmes PVD por espectroscopias de absorção no ultravioleta-visível (UV-vis), no infravermelho com transformada de Fourier (FTIR), espalhamento Raman, difração de raios-X, microscopias óptica e de força atômica (AFM) e caracterização elétrica cc (tensão x corrente). Os resultados mostraram que é possível a fabricação de filmes PVD de ZnPc e NiPc, uma vez que estas moléculas não são termicamente degradadas durante o processo de evaporação térmica a vácuo, e que o crescimento dos filmes pode ser controlado em escala nanométrica para ambos os materiais. Em termos estruturais, os filmes PVD de ZnPc e NiPc são cristalinos (forma α) e possuem as moléculas arranjado-se na forma de agregados e monômetros e ordenadas com o anel macrociclo inclinado em relação à superfície do substrato. Tais agregados podem ser vistos em escala nanométrica, porém, em escala micrométrica os filmes apresentam-se morfologicamente homogêneos. Em relação às propriedades ópticas e elétricas, observou-se que ambos os filmes PVD absorvem na região do visível com a ZnPc apresentando fotoluminescência quando irradiado com laser 785 nm. A condutividade elétrica é de 1,2x'10 POT. -10' S/m para a ZnPc e de 72x'10 POT...
In this work thin films of phthalocyanines of zinc (ZnPc) and nickel (NiPc) were fabricated through the vacuum thermal evaporation technique (PVD - physical vapor deposition) for different thicknesses at nanometric scale with the objective of determining the molecular architecture of these films as well as their optical and electrical properties. The final idea is to generate subsidies for applications of these films in electronic devices based on organic semiconductors and gas sensors. The PVD films were characterized using thermogravimetry (TG), differential scanning calorimetry (DSC), ultraviolet-visible (UV-vis) and Fourier transform infrared (FTIR) absorption spectroscopies, Raman scattering, X-ray diffraction, optical and atomic force (AFM) microscopies, and electrical characterization (tension x current dc). The results showed that the fabrication of ZnPc and NiPc films is possible since these molecules are not thermally degraded during the process of vacuum thermal evaporation and that the growth of the films can be controlled at nanometric scale for both materials. Structurally, the PVD films of ZnPc and NiPc possess the molecules organized with the macrocycle ring tilted in relation to the substrate surface. They are crystalline (α form) and possess molecular aggregates in the form of dimmers or higher order of aggregates and monomers. Such aggregates can be seen at nanometric scale, however, at micrometric scale the films are morphologically homogeneous. In relation to the optical and electrical properties, it was observed that boh PVD films absorb in the visible region with the ZnPc presenting photoluminescence when irradiated with the 785 nm laser line. The electric conductivity at 1,2x'10 POT. -10' S/m for ZnPc and 72x'10 POT. -10' S/m for NiPc. They also presented photoconductivity with the ZnPc more photoconductor than NiPc. Finally, after thermal treatment... (Complete abstract click electronic access below)
In this work thin films of phthalocyanines of zinc (ZnPc) and nickel (NiPc) were fabricated through the vacuum thermal evaporation technique (PVD - physical vapor deposition) for different thicknesses at nanometric scale with the objective of determining the molecular architecture of these films as well as their optical and electrical properties. The final idea is to generate subsidies for applications of these films in electronic devices based on organic semiconductors and gas sensors. The PVD films were characterized using thermogravimetry (TG), differential scanning calorimetry (DSC), ultraviolet-visible (UV-vis) and Fourier transform infrared (FTIR) absorption spectroscopies, Raman scattering, X-ray diffraction, optical and atomic force (AFM) microscopies, and electrical characterization (tension x current dc). The results showed that the fabrication of ZnPc and NiPc films is possible since these molecules are not thermally degraded during the process of vacuum thermal evaporation and that the growth of the films can be controlled at nanometric scale for both materials. Structurally, the PVD films of ZnPc and NiPc possess the molecules organized with the macrocycle ring tilted in relation to the substrate surface. They are crystalline (α form) and possess molecular aggregates in the form of dimmers or higher order of aggregates and monomers. Such aggregates can be seen at nanometric scale, however, at micrometric scale the films are morphologically homogeneous. In relation to the optical and electrical properties, it was observed that boh PVD films absorb in the visible region with the ZnPc presenting photoluminescence when irradiated with the 785 nm laser line. The electric conductivity at 1,2x'10 POT. -10' S/m for ZnPc and 72x'10 POT. -10' S/m for NiPc. They also presented photoconductivity with the ZnPc more photoconductor than NiPc. Finally, after thermal treatment... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Ciencia, Zinco, Niquel, Tecnologia de materiais, Filmes evaporados a vácuo (PVD), Arquitetura molecular, Zinc phthalocyanine, Nickel phthalocyanine, Vacuum evaporated films, Molecular architecture, Electrical and optical properties
Como citar
ZANFOLIM, Antonio Aparecido. Fabricação e caracterização estrutural de filmes evaporados de ftalocianinas. 2009. 135 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências de Bauru, 2009.