Introducing XIS, A New Integrated Device and Module Concept

In this paper we introduce a new device concept for high efficiency, low cost, wafer-based silicon solar cells. To significantly lower the costs of Si photovoltaics, high efficiencies and large reductions in the bill of materials, especially for metals and silicon, are required. The reduction of the amount of metal in wafer-based silicon modules requires adaptation of the device architecture into low-current devices. Basically, this comes down to reducing cell dimensions in the direction of current flow. The XIS (Crystalline Silicon Interconnected Strips) device concept addresses this significant reduction in the consumption of metals and enables the use of ultra-thin silicon wafers. In combination with a high efficiency back-contact heterojunction device geometry a cost reduction to below 0.5 /Wp is foreseen. The integrated device and module concept can be realized with standard industrial production processes. The concept relies on the high efficiencies that can be achieved with crystalline silicon wafers, in combination with the high throughput that can be achieved with thin-film manufacturing technology. First devices have been realized demonstrating the principle of a series connected back contact hybrid silicon heterojunction module concept.