Implementation of an IoT-based Dip Coating System for The Fabrication of ZnO Thin Film

Abstract The aim of this work is to develop an Internet of Things (IoT) based automatic dip-coating system for fabricating thin films. The main disadvantages of commercial dip-coating systems are their initial calibration complexity and the inability to handle operations through smartphones. The developed dip-coating system can be operated through smartphones and achieves dipping and withdrawal speeds ranging from 1 to 100 mm/min without disturbances caused by vibrations. The total expenditure for the IoT-based dip coater is below one hundred dollars, making it suitable for large-scale production. The structural properties, optical properties, surface morphology, and surface chemistry of ZnO thin films prepared by commercial, existing automatic, and developed IoT-based dip coating systems are investigated for performance comparison. ZnO thin films are successfully deposited on glass substrates, with the dipping process performed five times using a 1M concentration to achieve the desired film thickness. X-ray diffraction (XRD) analysis reveals that ZnO possesses a hexagonal Wurtzite crystal structure. Scanning Electron Microscope (SEM) inspections show uniform layers, and chemical properties are analyzed using Energy-dispersive X-ray Spectroscopy (EDS). The thin films demonstrate over 80% optical transmittance in the 380 to 900 nm wavelength range. This inexpensive equipment supports scientific advancement for researchers unable to afford costly commercial systems, producing thin films with uniform thickness in the nanoscale range, revealing the effectiveness of the dip-coater.