FABRICATION OF POLYANILINE THIN FILMS AND CHARACTERIZATION OF ITS ELECTRONIC AND PHOTOPHYSICAL PROPERTIES

• Main Author: Sudirman
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/34120
• Institution: Institut Teknologi Bandung

Conducting polymers are potentially to be developed as organic semiconductor materials, which have applications in various electronic devices such as organic rectifier diodes, organic photovoltaic cells, p-n junction solar cells, etc. Polyaniline (PANI) is one of conducting polymers that has several advantages compared to other conducting polymers. For example, it is easy to synthesize, good stability has multi-level oxidation, wide range of conductivity, and relatively cheap monomers compared to other conducting polymers. However, the major obstacle in application of PANI, as demonstrated its poor solubility in common solvents, makes it difficult for fabrication, especially in the form of thin films on various substrates. In this study, a proccessable PANI was developed through solvothermal method using an autoclave with a suitable solvent. Here, the solvents were chosen based on their Hildebrand solvent parameters relative to PANI-EB, namely NMP (N-methyl- pyrrolidinone) which was the most used solvent, DMAc (Dimethylacetamide) and diethyl ether. The experimental results showed DMAc as the most suitable solvent as reflected by its maximum solubilty of 7.39 % (w/w). The product of DMAc solvothermal treated PANI produce homogeneous film with high conductivity that reached 1.14 S/cm, while the NMP treated one (Cmax = 3.43 % (w/w) produce inhomogeneous film with much lower conductivity of 0.20 S/cm. In the case of diethyl ether solvothermal treated PANI, it did not produce soluble PANI, even though treated at its critical condition. Here, the produce PANI-ES shows lower conductivity of 0,031S/cm than PANI-ES standard of 0.042 S/cm. Since then, the PANI films that processed with DMAc were characterized further. They showed the following electronic transitions: ?b ? ?? (4.4 eV), ? ? P1 (3.21 eV), ? ? ? ? ? ?q (1.98 eV), and ?? ? ?q (2.23 eV) as revealed by UV-Vis absorption and photoluminescence. The transformations of structural conformation due to doping were studied using Raman and FT-IR spectrocopies, which showed the tendency of more symmetrical conformation. The resulting PANI-ES film were deposited on n- type silicon wafer, and then tested as diodes with p-n structure. I-V curves of the diodes showed rectifier characteritics.