Solar Cell Imaging: A Gateway to Stem Disciplines

In this project, we are using image processing (both visible, near infrared, and far infrared) to study various aspects of solar cells including their materials, device operation, defects, variability, and reliability. Laboratory projects using low-cost fluorescent cameras, visible and near-IR cameras, and far-infrared thermal cameras are used to characterize the grain structure, defects, surface roughness, reflectivity, electroluminescence, photoluminescence, and photovoltaic operation of solar cell materials (e.g., monocrystalline and multicrystalline silicon wafers), thin-film and nano solar cells, commercial silicon solar cells, and photovoltaic modules. Students can import captured images into MATLAB or other widely-available image processing software for analysis and interpretation. Topical laboratory modules and projects are being developed suitable for on-line delivery. Overview, Purpose and Broad Aims: The purpose of this work is to develop, validate, and disseminate a series of laboratory/classroom educational modules that use image capture, image processing and image analysis of photovoltaic solar cells to teach concepts and methods in: • materials science and semiconductor technology including image-based studies of electrical and optical properties and defects, and image analysis of features at several scales (submicron, micron, mm), as well as packaging, area variability and yield. • surface metrology (e.g., micro roughness, cleanliness and surface damage, etching uniformity, and characteristic geometries of microstructured surfaces) • metallography (microstructure such as grain boundaries and texture, i.e., preferred grain orientations and size distributions and their impact on material performance) • thin-film optics such as anti-reflection coatings • many aspects of photovoltaics and other optoelectronic devices such as LEDs, sensors, flat panel displays, and other energy conversion devices such as photocathodes • basic ideas of hyperspectral and remote imaging • radiative, conductive, and convective heat transfer; and various heating and cooling methods (resistive heating and convective heating/cooling, thermoelectric (Peltier) effects, optical heating with lasers and flash lamps, ultrasonic heating) • thermal and infrared physics, as particularly related to thermal imaging and IR optics