Solar Cell Development

FLIR Systems cameras used to monitor active volcanoes

The environmental and political benefits of renewable energy sources are understood by anyone even mildly interested in the future of our planet. Solar cells are getting a lot of attention because they are not only a clean source of renewable energy, but also because their energy input is essentially free. They use photovoltaic (PV) technology to make a direct conversion of the sun's rays into electricity. According to John Boyd, a technology analyst at Semiconductor Insights, "a solar array 150 x 150 km could, in principle, meet all of North America's energy needs." [1] Assuming adequate installation space, and a solution for power grid load balancing, the main problem to be solved is achieving grid parity, the point at which the cost of generating PV power is competitive with that of generating power using existing power plants.

Currently, the cost of generating PV power is approximately $0.20/kWh globally, roughly twice the rate of coal-based alternatives. Silicon solar cells are achieving conversion efficiencies between 15% and 25%, while typical metallic thin film cells have efficiencies in the 5% to 20% range, depending on materials used. R&D efforts are aimed at increasing the efficiency of both solar cell technologies and reducing PV cell power generation costs to around $0.05/kWh.

The primary challenges in reducing the cost of PV power generation exist in the production phase of the development cycle. Too many defects in the semi-conducting material structure go undetected before solar cells are put into use. Identifying these defects requires efficient, cost effective test and measurement methods for characterizing a cell's performance and its electronic structure.

This paper is an overview of the methods in which FLIR Infrared Cameras can be used to characterize solar cell performance.

Figure 1. Solar cell testing using an uncooled microbolometer handheld camera.