Improving the Mathematical Model for Luminescent Down-Shifting Layers by Investigating their Loss Mechanisms

Abstract

A Luminescent Down-Shifting (LDS) layer is an optical approach to improve the solar cell’s optical response by using luminescent species doped in a polymer matrix material to form a thin layer to be deposited on top of the PV solar cell. In this article, the performance of different polymer matrix materials with various loss mechanisms (attenuation and scattering losses) are mathematically modeled based on a ray tracing algorithm. The simulation is carried out with and without counting the loss mechanisms in the mathematical model. First, the model studied the performance of LDS layer (12.49 × 12.49 × 0.015 cm) of Europium complex (Eu) doped in a Polyvinyl Acetate (PVA) film and deposited on top of monocrystalline Silicon (c-Si) under standard AM1.5 global solar radiation. The comparison of the modelling and experimental results proved that the model’s discrepancy was improved from 27% to 2% when the loss mechanisms of the matrix materials are counted in the model. Optical efficiency of 80% was obtained for the LDS layer and an excellent agreement has been achieved between the experimental and model results. Subsequently, the model was used to study the performance of other matrix materials such as glass, epoxy resin polymer, and Poly Methyl Methacrylate (PMMA) polymer for their loss mechanisms. The results have shown that although these polymer are transparent above 300 nm, their optical response significantly changes in the region between 300 to 400 nm hence the optical efficiency and response of the LDS layer.