Essential parts of solar panels are photovoltaic (PV) films, which transform light from the sun into electricity. The refractive index, transmittance, and reflectance of these films have a major impact on the overall efficiency and light loss of photovoltaic modules. The optical characteristics of three often used PV film materials—Polyolefin Elastomer (POE), Ethylene-Vinyl Acetate (EVA), and Expanded Polyethylene (EPE)—are thoroughly analyzed in this article. We investigate the variations in their photovoltaic conversion efficiency and light loss, as well as their influence on PV module performance, by contrasting their refractive indices, transmittance levels, and reflectance properties.

Index of Refractiveness

The internal reflection and light propagation within the solar cell structure are influenced by the refractive index of a PV film material. Films made of POE, EVA, and EPE usually have distinct refractive indices. In general, POE films have a higher refractive index than EVA and EPE films. Increased light trapping inside the solar cell can result from a greater refractive index, increasing the likelihood of light absorption and electron production. EVA and EPE films, on the other hand, have lower refractive indices, which could lead to increased light reflection at the film-air contact and possible light loss.

Transmission

The term “transmittance” describes a photovoltaic film’s capacity to let light through. It has a significant impact on how much incident light enters the solar cell. Because of their high optical transparency, which permits a large amount of light to pass through them, EVA films are well-known for their transparency. By optimizing the quantity of sunlight that reaches the solar cell, this high transmittance contributes to a higher photovoltaic conversion efficiency. Effective transmittance qualities are also demonstrated by POE films, but at somewhat lower values than those of EVA films. Since EPE films feature closed cells, which restrict light flow, they often have poorer transmittance. Variations in transmittance between these layers may have an impact on the PV module’s total energy yield.

Luminance

The fraction of incident light that a photovoltaic film’s surface reflects back is known as reflectance. Reduced energy conversion efficiency and light loss are possible consequences of high reflectance. Because of their low reflectivity, EVA films are renowned for letting in a large amount of incident light into the solar cell. This feature improves the PV module’s overall performance and reduces light loss. Additionally, POE films have relatively low levels of reflectance, which helps to maximize the use of available light. EPE films may have higher reflectance values than EVA and POE films because of their closed-cell structure and reduced transmittance. As a result, there can be more light loss and less effective energy conversion.

Effect on the Performance of Photovoltaic Modules

The photovoltaic conversion efficiency and overall performance of PV modules are directly impacted by the optical characteristics of PV films, such as refractive index, transmittance, and reflectance. Higher refractive indices can improve the solar cell’s ability to capture and absorb light, which will increase electron generation and efficiency. More incident light can reach the solar cell at higher transmittance levels, which boosts energy generation. Reduced reflectance levels increase overall module performance and reduce light loss. Consequently, a PV module’s performance and energy production can be greatly affected by the PV film material selection.

The refractive index, transmittance, and reflectance of PV films are important optical characteristics that affect how well solar panels operate and how efficient they are. POE and EVA films have desirable optical properties including low reflectance, high transmittance, and moderate refractive indices; on the other hand, because of their closed-cell structure, EPE films usually have lower transmittance and possibly higher reflectance. Manufacturers and researchers of solar panels can make well-informed decisions about material selection, photovoltaic conversion efficiency optimization, and light loss minimization in PV modules by carefully examining these films’ optical properties.