The encapsulation layer of solar panels, including solar films, typically consists of materials that provide protection to the sensitive photovoltaic cells while ensuring transparency to allow sunlight to pass through. The most common materials used in the encapsulation layer of solar panels include:

Ethylene-Vinyl Acetate (EVA)

EVA is one of the most widely used materials for encapsulating solar panels. It is a transparent and flexible polymer that effectively bonds the various layers of the solar panel together while providing protection against moisture, dust, and mechanical stress. EVA is thermally laminated onto the solar cells during the manufacturing process.

Polyvinyl Butyral (PVB)

PVB is another polymer commonly used in the encapsulation layer of solar panels. It offers excellent adhesion properties and durability, making it suitable for both crystalline silicon and thin-film solar panels. PVB is often used in applications where enhanced durability and resistance to yellowing over time are desired.

Ethylene-Tetrafluoroethylene (ETFE)

ETFE is a fluoropolymer that has gained popularity in recent years due to its exceptional transparency, flexibility, and durability. It is commonly used in lightweight and flexible solar panels, including solar films, where weight reduction and resistance to harsh environmental conditions are important.


In some cases, especially in traditional glass-fronted solar panels, tempered or laminated glass is used as the encapsulation material. Glass provides excellent protection against moisture, UV radiation, and mechanical impact while maintaining optical clarity. However, it adds weight to the solar panel and may not be suitable for flexible or lightweight applications.

Polyethylene Terephthalate (PET)

PET is a thermoplastic polymer commonly used as a substrate or protective cover sheet in solar panels. While it is not typically used as the primary encapsulation material, PET films can provide additional protection against moisture and physical damage in conjunction with other encapsulation materials.

These materials may be used alone or in combination with each other to create multi-layered encapsulation structures tailored to specific performance requirements and environmental conditions. The choice of encapsulation material depends on factors such as panel design, application, durability requirements, and cost considerations.