نسترن راگردي كاشاني

This thesis examines the fabrication and characterization of flexible photodetector electrodes made of graphite on paper substrates and uses pulsed laser patterning as a key method to increase patterning accuracy. The final goal of this research is to create a cost-effective, environmentally friendly and suitable alternative for the manufacture of light detectors, with an emphasis on scalability and practical application in flexible electronics. Graphite, known for its high electrical conductivity, availability and ease of processing, is used as the electrode material. Paper, chosen for its flexibility, biodegradability and low cost, serves as the substrate. The main innovation of this work lies in the use of laser patterning to precisely modify the graphite layer, improving the electrical and optical properties of the electrodes. This method provides the possibility of controlled ablation of graphite, optimization of factors such as electrode surface, conduction paths and light absorption capability. In this research, various laser parameters, including pulse duration, speed, and repetition rate are investigated to determine their effect on electrode performance. A comprehensive set of experiments has been performed to eva‎luate electrical conductivity and surface morphology. The findings show that patterning with pulsed laser significantly increases the accuracy of the graphite optical detector electrode design on paper and leads to the improvement of electrical conductivity and optical response. Flexible electrodes exhibit excellent mechanical stability, which makes them suitable for use in wearable sensors, flexible displays, and other portable optoelectronic chips. Expanding research on flexible detectors and sensors also highlights its potential to contribute to the development of sustainable and high-performance electronics. This research paves the way for future developments in green electronics and emphasizes the importance of innovative fabrication methods in achieving next-generation flexible devices.

كندگي ليزري , الگودهي ليزري , گرافيت , الكترود , آشكارساز نور , كاغذ

laser ablation , laser patterning , graphite , electrode , light detector , paper

Nastaran Ragerdi Kashani

Dr. Mohammadreza Jafarfard - Dr. Hedieh Pazokian