Fresh on the heels of a new efficiency record reported for perovskite-silicon tandem solar cells, a similar achievement has been posted for sulfide kesterite. University of New South Wales, Australia, researchers achieved an 11% conversion efficiency for this emerging photovoltaic material composed of abundant and inexpensive copper, zinc, tin and sulfur.

The thin-film semiconductor material is derived from copper indium gallium (di)selenide, a proven high-An 11 percent conversion efficiency was documented for sulfide kesterite (Cu2ZnSnS4, also referred to as CZTS). Source: University of New South Walesefficiency, thin-film composition that can be applied to flexible surfaces. However, the indium component is rare and relatively expensive, due to high demand for its use in flat panel displays. The goal of relying on low cost, non-toxic and abundant components is fulfilled by substituting zinc and tin for indium and gallium.

Sulfide kesterite also has the advantage of being easily integrated into existing manufacturing processes. It can also be incorporated into tandem cells with silicon as its bandgap can be easily tuned over a wide range when alloying with other ingredients.

While the energy efficiency level of about 30% requisite for cost-effective commercial applications has yet to be demonstrated, the researchers are optimistic about reaching this target in the near term.