Laser assisted wet texturing of flexible polyethylene terephthalate substrate using Nd3+:YAG laser for photovoltaics devices

Abstract

In this research, a successful methodology of laser assisted wet texturing (LAWT) of flexible polyethylene terephthalate (PET) is demonstrated. The texturing is carried out employing third harmonics (355nm) wavelength of solid-state Nd3+:YAG laser. The inactive textured flexible substrate is applicable for enhancement of light trapping efficiency (LTE) of solar cell. Achieving textures on the PET is challenging, due to its sensitivity to heat input. The heat input is studied theoretically to determine the parameters window for the experimentations. Using simulation results, three different fluences 10 (poly-crystalline region), 30 (crystalline region) and 50 (ablation region) J/cm2 were used for LAWT. The samples were investigated using field-emission scanning electron microscopy (FE-SEM), and the localised effects in structures were analysed using X-ray diffraction (XRD), Raman and UV–Vis absorption spectroscopy. Furthermore, for the device development, the sputter-deposited rear electrode of Tungsten (W) over textured PET substrate shows an increase in the UV–Vis absorption.