Extraction and analysis of back-sheet layer from waste silicon solar modules

Abstract

The back-sheet shields the solar panel from UV rays, moisture, dust, and other environmental factors. With the enormous growth of the solar industry year after year, the demand for recycling is also increasing rapidly. In the present study, the back-sheet layer was extracted from a waste crystalline silicon PV module by thermally heating the module at 130˚C temperature. Various characterization techniques, including Raman, FTIR, SEM-EDAX, XRD, and TGA, were used to examine extracted back-sheet layer properties for its reuse. The Raman and FTIR spectra of extracted back-sheet are quite similar to those of reference PET back-sheet, indicating that no significant changes in composition occurred during the extraction process. The extracted back-sheet has a composition of carbon and oxygen as witnessed from EDAX spectroscopy. The extracted back sheet maintained its semicrystalline behavior as that of the reference back sheet, observed by XRD spectroscopy. Thermogravimetric analysis revealed that the thermal stability of extracted back-sheet is up to 252˚C in the air environment and up to 315˚C in the inert environment. Thermal degradation of extracted back-sheet is a two-step process in an air environment observed by differential thermogravimetry. The observed properties of extracted back-sheet are comparable to those of commercially available back-sheet, and the same may be reused in solar and polymer industries after appropriate processing.