An efficient screening strategy for hindered amine light stabilizers in EVA photovoltaic encapsulation films and experimental validation

The photostability of Ethylene-vinyl Acetate copolymer (EVA) photovoltaic encapsulation films is highly dependent on the Hindered Amine Light Stabilizer (HALS) used. However, the extensive screening of HALS via long-time aging tests is time-consuming and high-cost, hindering the design of EVA photovoltaic films with higher stability. In this paper, an efficient screening strategy for selecting optimal HALS for EVA was proposed based on molecular simulation and validated via long-time aging experiments. Firstly, several molecular simulations were performed to analyze three critical parameters: chemical activity, migration resistance, and compatibility with the EVA matrix of six HALS. The simulation results identified HALS-4 exhibiting optimal characteristics including high radical scavenging activity, superior migration resistance, and complete compatibility with EVA, suggesting its potential as an optimal HALS. Subsequently, it was found by long-term aging experiment combined with Fourier-Transform Infrared Spectroscopy and rheological analyses that EVA films undergo severe photo-degradation without HALS, while the incorporation of HALS delayed aging. Importantly, the anti-aging performance varied markedly among different HALS types, with HALS-4 exhibiting superior stabilization effects. Finally, based on the analysis of the experimental and molecular simulation results, it can be concluded that the computational predictions showed excellent agreement with experimental results of HALS-4′s outstanding anti-aging performance, thereby validating the rationality of the proposed screening strategy. The strategy presented in this work offers theoretical guidance for the development of high-performance HALS and provides an efficient tool for the design of EVA photovoltaic encapsulation films with higher photostability.