ReRa LumiQuest EL-system – Electroluminescence pictures of solarcell materials
To follow the growing demand on more accurate analysis tools for solar cell materials, we present the LumiQuest electroluminescence system. As an IR camera specialist we have been providing scientific laboratories with high quality cameras. These cameras are often used to capture the electroluminescence (EL) images of solar cell materials. The quality of these images is strongly dependent on the probing technique used. To obtain an EL image, the solar is cell is kept in forward bias, while the current is held constant by a single quadrant power-supply. These currents can be relatively large. For standard 6”x6” silicon solar cells it is common to use 3A - 10A. At such current levels the series resistance effects near the contact points is significant. The resulting EL image of the solar cell is no longer determined by the material, but by the contacting technique. Because the current is taken from one point on the solar cell, it will be interacting with the solar cell at that location only, resulting in a huge signal around the probing position. It would be better for the current to exit the cell over a uniformly distributed area.
This is where the LumiQuest has a significant advantage. Many years of experience in solar cell probing from our Dutch partner ReRa Solutions is used to design a probe-station that uniformly distributes the electrical current resulting in EL images that 100 % reflect the material quality. The probe-station has a low resistance conductive area with 3 vacuum zones. A pump to mount the solar cell wafer is provided. Spring loaded probes are evenly distributed over the solar cell bus-bars and can be adjusted to most common silicon wafer based cells.
Dependant on the required wavelength range LumiQuest can be equipped either with our cooled CCD cameras from Aplegen Inc. or with our Xeva 320 or Xeva640 Near Infrared cameras.
It is blocking all the light from the environment. The 15V, 10A low noise power-supply realizes the stable, current controlled forward bias. Please contact us if you need more information on the complete system or the available cameras.