Optimization of high efficiency amorphous silicon alloy based triple-junction modules

A systematic approach has been used to scale up high efficiency 0.25 cm{sup 2} active-area amorphous Si alloy based triple-junction devices to high-efficiency encapsulated modules of aperture area {approximately}920 cm{sup 2}. In order to analyze the losses involved in the scale-up, intermediate aperture area, 40 cm{sup 2} and 450 cm{sup 2}, modules have also been fabricated. The best stable active-area efficiency obtained on the small-area cells is 12.9%. The best initial efficiency of a {approximately}920 cm{sup 2} aperture area encapsulated module is 12.1%. National Renewable Energy Laboratory (NREL) has independently light soaked three of the {approximately}920 cm{sup 2} modules. They have measured a stable efficiency of 10.5% which represents a new world record. This paper presents various aspects of the large-area module work.