Improve the Photoelectric Properties of Transparent Insulating Films Through Simple Mechanical Pressure Treatment

In this study, a transparent insulating film that possesses high visible light transmittance, high resistivity, and excellent resistance to potential-induced degradation (PID) is developed via a simple and innovative physical modification technique. By employing mechanical pressure treatment (MPT), the internal porosity of the ethylene vinyl acetate copolymer (EVA) film is decreased. This results in a 0.5% increase in average transmittance and a theoretically calculated enhancement in photovoltaic (PV) cell efficiency of over 0.1%. Additionally, the pores of the EVA film become denser, effectively suppressing leakage current carriers induced by structural defects. As a result, the volume resistivity of the EVA film is significantly improved, with increments of 36% and 48% at room temperature and 60°C, respectively. Compared to conventional chemical modification approaches, this MPT technique significantly improves the defects of the film during the film-forming process without altering its structure or negatively affecting the properties of the packaging material. This method also demonstrates a reduction in the migration of Na⁺ from the PV module glass to the cell, thereby improving the performance of the module. When integrated with light-induced recovery (LIR) encapsulation protocols, the optimized EVA film represents a promising and cost-effective solution for mitigating PID in commercial PV systems. This advancement provides critical insights into defect engineering for polymeric encapsulants while offering industrially scalable processing advantages.