Fabrication Study Of Photoluminescent Ethylene-Vinyl Acetate Encapsulant For Photovoltaic Solar Cells

Encapsulant materials in photovoltaic(PV) modules have great influence on the output efficiency and service lifetime of PV system. In this paper, photoluminescent ethylene-vinyl acetate copolymer(EVA) encapsulant for PV solar cells was investigated and fabricated. An increase in the power conversion efficiency of PV solar cells might be expected through the down-conversion effect of photoluminescent EVA encapsulant by which the ultraviolet light not absorbed by the Si solar cells could be converted to visible or near-infrared light.Firstly, based on our previous research work on EVA encapsulant, acrylic acid(AA), methyl methacrylate(MMA) and g-methacryloxypropyl trimethoxy silane(KH-570) were chosen as grafting monomer of EVA, The influence of grafting monomer and stabilizer content on EVA encapsulant property were studied in detail through cross-linking property, light transmittance property, adhesive property characterizations and damp-heat aging test. Results showed that the EVA encapsulant grafted by KH-570 had the best comprehensive performance.Secondly, Lead thiobenzoate(PbTB) precursor was successfully synthesized by lead acetate and thiobenzoic acid as raw materials. Then the lead sulfide(Pb S) quantum dot was prepared through the decomposition of lead thiobenzoate precursor in oleylamine(OLA).X-ray diffraction characterization confirmed the crystal structure of PbS and transmission electron microscopy(TEM) showed the diameter of PbS particles was about 10~20nm.Finally, the photoluminescent EVA encapsulant was fabricated through three different ways: direct blending of EVA resins and PbS quantum dot, thermal decomposition of PbTB, and in-situ reaction of Pb TB and OLA. Light transmittance property and photoluminescence property characterizations indicated that photoluminescent EVA encapsulant fabricated by in-situ reaction of PbTB and OLA had better performance over the other encapsulants.