Progress in CIS-Based Module Development

Alloys of copper indium diselenide are the most promising candidates for reducing the cost of photovoltaics below the cost of crystalline silicon. Small area, fully integrated modules exceed 13% in efficiency and long-term outdoor stability has been demonstrated. The availability of natural resources and environmental impacts appear acceptable. Challenges remain to scale the process to largerarea and to pass accelerated environmental testing. Process scale-up is systematically proceeding from the foundation of a reproducible small area module process with low variation; however, large-area circuit performance has not yet achieved the same level as the baseline process. Differences in performance between the baseline and large area processes have been isolated to differences in theequipment used to form absorbers and is the subject of current development. The impact of larger part size has been tested for each process step using the demonstrated baseline process. Results indicate that larger-area parts will achieve the performance level of the baseline process. This paper will outline the status and prospects for CIS-based photovoltaics and discuss efforts at SiemensSolar Industries to scale up to larger circuit area and to pass accelerated environmental tests.