Numerical Simulation of Luminescent Downshifting in Top Cell of Monolithic Tandem Solar Cells

Mahfoud Abderrezek,Mohammed Ayad,Mohamed Fathi,Farid Djahli

doi:10.1155/2013/480634

Mahfoud Abderrezek, Mohammed Ayad + Show 2 more

Open Access

https://doi.org/10.1155/2013/480634

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Abstract

The increase in the conversion efficiency of monolithic tandem solar cells is limited by the short-circuit current density matching between the top and the bottom cells. Generally, the top cell presents the lowest current in the two subcells. In this paper, in order to increase the short-circuit current density in the top cell, we present a theoretical survey of the luminescence downshifting (LDS) approach for the design of monolithic tandem solar cells. The photovoltaic (PV) glass encapsulation material is replaced with a polymer material of polymethyl methacrylate (PMMA) type which is doped with diverse kinds of organic dyes. The performance of the n-p-p+ GaInP structure has been simulated as a function of the organic dyes. Gains achieved for the short-circuit current density and conversion efficiency are, respectively, 13.13% and 13.38%, under AM1.5G illumination spectra.

Highlights

Multijunction solar cells can increase the efficiency of the cell by introducing another semiconductor able to reduce losses in high energy photons
The performance of the GaInP solar cell was simulated without an luminescence downshifting (LDS) layer, and the obtained results were in accordance with those in the literature [21]
When an LDS layer is introduced on the top of the solar cell, organic dyes produce a substantial modification on the incident AM1.5G spectrum; they oblige the photons in the ultraviolet region to shift towards the visible region

Summary

Introduction

Multijunction solar cells can increase the efficiency of the cell by introducing another semiconductor able to reduce losses in high energy photons. We propose an alternative method to increase the short-circuit current density in the top cell, based on the manipulation of the incident spectrum before its absorption by the solar cell; the idea is to substitute PV glass encapsulation materials with a thin layer of polymer material PMMA doped with optically active components. It has been shown in previous works that this approach results in performance improvement on some single junctions (CdTe, mc-Si, c-Si, GaAs, and CIGS) [5,6,7]. It reduces the cost and weight of the final PV module

Materials and Methods

Simulation Results and Discussions

Conclusion