Ultraviolet to visible down conversion of SiO2-Ce3+, Tb3+ nanospheres-poly-EVA films for solar cell application

Abstract

Despite the many advantages which the conventional crystalline silicon solar cells (c-Si) have over other forms of renewable energy sources, they still have major drawbacks (energy loss) limiting their performance. One of the main reasons for energy loss is the ineffective utilization of short wavelength photons, especially within the UV region. The efficiency of the c-Si solar cell device can be improved by depositing the phosphor nanoparticle on top of the devise to capture and covert the UV photons from sunlight to visible or near infraded photons by a downcoversion process. Therefore, we have prepared and investigated luminescent and optical properties of downconverting nanophosphors composed of SiO2 co-doped with Ce and Tb. The dominant photoluminescence emission peak was observed at 544 nm and it was attributed to the D-5(4) -> F-7(5) transition of Tb3+. The phosphors synthesized were incorporated into poly poly-ethylene vinyl acetate (poly-EVA) films which were later overlaid on a commercial silicon solar cell to and its photocurrent efficiency were measured. The phosphor films recorded a significantly good transmittance (>= 76%) and also displayed a UV absorption capacity compared to that of the plain poly-EVA film. Some of the films made from different concentrations of Ce and Tb, recorded an increase in the photocurrent efficiency when deposited on the solar cell, while other compositions recorded marginal decreases compared to that of the plain EVA film.