Ultraviolet fluorescence of ethylene-vinyl acetate in photovoltaic modules as estimation tool for yellowing and power loss

The potential of ultraviolet (UV) fluorescence as a field technique for photovoltaic module defect detection was demonstrated recently. Here we study the formation rate of the fluorophores in module encapsulating material under UV illumination. We observe a correlation between the decrease in visible light transmission of the encapsulant and UV fluorescence intensity. This correlation allows estimating the yellowing-induced power loss via fluorescence measurements.