Transparan ve iletken tek duvarlı karbon nanotüp ince filmlerin hazırlanması

Carbon nanotubes (CNTs) are today one of the key elements of nanotechnology and are most intensively investigated materials. CNTs are a unique material with their high mechanical, electrical, optical, thermal and chemical properties that may be useful in a number of applications. The versatile properties of carbon nanotubes make its suitable for use in various transparent and conductive optoelectronic devices. Transparent and conductive electrodes are being utilized in solar cells, organic light emitting diodes (OLEDs), touch panels and many other optoelectronic devices. Among them indium tin oxide (ITO) is one of the most common materials. However, flexible, cost effective, conductive and robust single walled carbon nanotube (SWCNT) thin films can be preferred as an alternative to ITO electrodes. In addition, SWCNT thin film coating process does not need a vacuum system that can be applied at low temperatures via all solution based methods on several substrates over large areas. Spray and spin coating methods are more suitable deposition techniques for larger area applications. SWCNT thin films can easily be scaled up by utilizing a practical spray and spin coating setup for making transparent electrodes or thick SWCNT layers for other applications. In this thesis, transparent and conductive electrode was fabricated using SWCNTs. SWCNTs were firstly synthesized by chemical vapor deposition of acetylene on Fe/MgO catalyst at 800°C and purified by 3M HNO3 at 98.39 % purity level. Vacuum filtration and spray coating methods were utilized for the deposition of SWCNT. Several dispersing agents were investigated in order to achieve a homogeneous SWCNT solution, which were used in vacuum filtration and spray coating. After thin film deposition, optoelectronic properties were examined for different densities of SWCNT, surfactant and sonication procedure. Tip and bath sonicators were utilized due to homogeneous dispersion of SWCNT solution. In addition, acid and heat treatments were applied due to enhance the electrical conductivity of thin films. When compared to acid treatment and heat treatment, it has been found that heat treatment was more effective method to enhance optoelectronic properties of SWCNT thin films. The fabricated SWCNT thin films were characterized by scanning electron microscopy (SEM) and UV-vis spectrophotometer. Two point probe were utilized to determine the sheet resistance of SWCNT thin films on glass substrates that were deposited via vacuum filtration and spray coating methods. Thus, the efficiencies of thin films with fabricated different production parameters were determined and compared. In recent years, silver nanowires (AgNWs) have been receiving a lot of interest as a transparent conductive electrode material. It has been great material owing to the ease of nanowire manufacture, scalable solution. They possess high conductivity and mechanical ductility. They can be utilized in a network form like SWCNTs, therefore SWCNTs and AgNWs can be coated together on several surfaces homogeneously. In this thesis, AgNWs were also added to SWCNT solution in order to improve conductivity. The fabricated AgNW-SWCNT thin films were characterized by SEM and UV-vis spectrophotometer. Sheet resistances of the films deposited via vacuum filtration were also determined. It was found that the sheet resistance values decreased significantly to 95 Ω/sq.