Morphological, Optical, and Dielectric Properties of Chitosan Biopolymer Thin Films Synthesized by Spray Pyrolysis

The development of environmentally friendly devices using natural materials presents a significant challenge for researchers aiming to create more sustainable and eco-friendly technologies. Chitosan has garnered increasing attention in recent years due to its promising applications in transparent and flexible electronic devices, such as transistors and drug delivery systems. This study investigates the preparation of chitosan solutions that are deposited onto glass and indium tin oxide (ITO)-coated glass substrates via spray pyrolysis to produce thin films. These films are thoroughly characterized through optical, electrical, and spectroscopic analyses. The SEM image of the chitosan thin film demonstrates an overall uniform and relatively smooth surface, indicating that most of the chitosan was successfully deposited, forming a continuous layer. X-ray diffraction (XRD) analysis was conducted to examine the structural characteristics of the chitosan thin film, confirming its predominantly amorphous nature. UV-visible spectroscopy reveals that chitosan films display high transmittance in the wavelength range of 500-1500 nm, with a direct optical band gap of 4.14 eV. Fourier transform infrared (FTIR) spectroscopy identifies various functional groups in the chitosan powder, confirming its molecular composition. Additionally, at room temperature and a frequency of 1 kHz, chitosan demonstrates a dielectric constant of around 10, suggesting a favorable ability of dielectric energy storage; it shows promising results when used as a dielectric layer in transistor applications. The results also indicate promising sustainability aspects, with minimal solvent use and the possibility of material recovery after the process, addressing the current challenges in sustainable electronics. This study highlights the novelty of using chitosan for eco-friendly, high-performance electronic devices and provides new insights into its integration into next-generation technologies.