Fluoropolymers such as poly(tetrafluoroethylene-co-hexafluoropropylene) (Teflon
s
FEP), poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (Teflon
s
PFA) and poly(ethylene-co-tetrafluoroethylene) (Teflon
s
ETFE Film) have desirable optical and physical properties for optical applications in CPV.
Ethylene backbone polymers such as polyvinylbutyral (PVB) sheet (e.g., DuPont
TM
PV5200), and
ethylene co-polymers such as poly(ethylene-co-vinyl acetate) (EVA) (e.g., DuPont
TM
Elvax
s
PV1400),
and poly(ethylene-co-methacrylic acid metal salt) ionomer sheet (e.g., DuPont
TM
PV5300) have
applications as encapsulants in crystalline silicon (c-Si) and other flat plate PV applications. These
materials are available with both a wide variety of polymer compositions and additive packages which
affect their optical properties such as the UV absorption edge. Even materials such as DuPont’s Kapton
s
polyimide films, which are used behind the PV cell for their electrically insulating properties, have
optical requirements, and we have also characterized these materials.