SnS-based thin film solar cells: perspectives over the last 25 years

New types of thin film solar cells made from earth-abundant, non-toxic materials and with adequate physical properties such as band-gap energy, large absorption coefficient and p-type conductivity are needed in order to replace the current technology based on CuInGaSe2 and CdTe absorber materials, which contain scarce and toxic elements. One promising candidate absorber material is tin monosulfide (SnS). The constituent elements of the SnS film are abundant in the earth's crust, and non-toxic. If this compound is used as the absorber layer in solar cells, high efficient devices should be fabricated with relative low cost technologies. Despite these properties, low efficiency SnS-based solar cells have been reported up to now. In this work, we present a review about the state of the art of SnS films and devices. Finally, an analysis about different factors that are limiting high efficiency solar cells is presented.