Adjustable spectrum LED solar simulator

Abstract

An LED solar simulator containing LEDs emitting at 23 different wavelengths is described. Taking into account the natural spectral width of each of the LED wavelengths, a reasonably well-behaved and spike-free spectral continuum is demonstrated. The LED light source is based on a modular design that facilitates fabrication of arbitrarily large area simulators for both single solar cell and multi-cell module test and evaluation. The spectral tunability of this simulator makes it an attractive instrument for use in evaluating the performance of both conventional solar cells and tandem solar cells. The basic modular building block is a 10 cm x 10 cm “tile” consisting of the LED emitter platform with reflecting side mirrors and driver electronics conveniently located directly underneath the emitter platform in a compact yet flexible configuration. Combinations of tiles facilitate manufacture of solar simulators of arbitrarily large size and shape, with the advantages of high reliability, spectral tunability, lighter weight, no water cooling requirements and absence of high voltages. Excellent spectral mixing and intensity uniformity is obtained on the measurement plane, resulting in a simulator that meets Class AAA specifications according to ASTM and IEC standards.