Evaluating the effectiveness of optical coupling techniques

Abstract

It is important to maximize the amount of sunlight optically coupled into a solar cell. The usual approach to evaluate optical coupling is to fabricate solar cells and then to measure their performance under standard test conditions, using the short circuit current as the figure of merit. This approach suffers from several short comings, including spectral mismatch errors in the measurement and process induced variations in the performance. This paper presents an improved methodology for evaluating optical coupling, based on measuring the reflectance of sample surfaces as a function of wavelength. The effect of using this surface geometry on a particular cell can then be calculated using values of previously measured internal quantum efficiency for the cell technology selected. Data on a variety of surface texture treatments are presented.