Portable Sunlight To Assist Solar Cell Development

The National Institute of Standards and Technology (NIST) Physical Measurement Laboratory (PML) has announced the development of a laser-based solar simulator to be used in testing the performance of solar cells.
The conventional light source for testing PV materials is the xenon arc lamp, but it is difficult to focus and not ideal for testing recently developed multi-junction materials in which individual sections are designed to respond only to a particular spectral band.
Tasshi Dennis and John Schlager of the Quantum Electronics and Photonics Division at NIST’s Boulder, Colorado campus decided to exploit a technology that had just become commercially available – a “super-continuum” white-light laser system. The pair produced a design that makes controllable spectral modifications to the light and uses the output to illuminate different materials used in solar cells.
The researchers’ solar simulator generates a spectral distribution almost identical to sunlight and does so in an easily focused beam that can adapted be to examine the latest generation of nanoscale, multi-cell, and multi-layer PV configurations.
According to NREL researcher Daniel Friedman, who develops multi-junction concentrator cells, “The highest-efficiency solar cells use multiple junctions, with each junction tuned to a different slice of the solar spectrum. To test these multijunction cells, the spectrum of light from the solar simulator must be rapidly and accurately adjusted, which PML’s supercontinuum simulator provides.”
The system was recently tested  against the best xenon sources with very promising results and testing will continue on other PV materials, along with ongoing research into using a focused beam to produce spatial maps of materials.
Founded in 1901 and now part of the U.S. Department of Commerce, NIST is one of the nation’s oldest physical science laboratories. The mission of the Quantum Electronics and Photonics Division is to provide  comprehensive and technically advanced measurement capabilities and standards, as well as traceability to those standards.
Source/image source