Thin - film solar cell technologies based on Si with a thickness of less than a few
micrometers combine the low - cost potential of thin - film technologies with the advantages
of Si as an abundantly available element in the earth’s crust and a readily manufac -
turable ma te rial for photovoltaics (PVs). In recent years, several technologies have been
developed that promise to take the per form ance of thin - film silicon PVs well beyond that
of the currently established amorphous Si PV technology. Thin - film silicon, like no other
thin - film ma te rial, is very effective in tandem and triple - junction solar cells. The research
and development on thin crystalline silicon on foreign substrates can be divided into
two different routes: a low - temperature route compatible with standard float glass or even
plastic substrates, and a high - temperature route (600C). This ar ticle reviews the ma te -
rial properties and technological challenges of the different thin - film silicon PV ma te rials.