Engineering the Defects in CIGS films to Enhance Photovoltaic Efficiency

This SBIR Phase I project addresses Air Force requirements for lightweight, flexible, photovoltaic arrays for high specific power in space. Photovoltaic devices based on copper-indium-gallium-diselenide (CIGS) coated metal foil promise low cost, lightweight, high reliability and radiation hardness. But certain critical performance, processing, size and cost issues remain unresolved. This project will devise a single chemical processing step to reconfigure the deep defects in CIGS films. This processing step could potentially enhance the device performance, reduce air sensitivity and replace the hazardous processes used in state-of-the-art CIGS modules. Phase I will develop a surface engineering step to manipulate the CIGS defect density. Photocurrent and spectral response of modified CIGS films and devices will demonstrate proof-of-concept. The treatment step will use a remarkably simple but ingenious aqueous solution dip at room temperature. This step will precisely correct the defects that cause efficiency losses in defective or damaged CIGS films without etching off the material or depositing toxic cadmium sulfide buffer. It will be designed for easy and inexpensive implementation into existing CIGS photovoltaic manufacturing line.