Research: Next-Generation Photovoltaic Technologies
Stabilizing efficient photovoltaics from earth-abundant materials
Copper sulfide, Cu2S, functioned as the solar absorber in one of the first efficient thin film photovoltaics. However, large and uncontrollable electronic doping resulted in limited efficiency and ultimately, to poor solar cell stability.
Now, the allure of such an ideal solar absorber comprising these highly earth-abundant and non-toxic elements has stimulated new efforts to understand and stabilize the material.
Here, the surface of semiconducting Cu2S films are observed to oxidize in minutes under ambient atmosphere resulting in an orders of magnitude change in conductivity.
In order to address these instabilities, Argonne scientists have introduced the atomic layer deposition of a barrier layer to reduce the intrinsic doping and further slow the aging process, even in air. Taken together, these experiments detail a mechanism for the environmentally induced degradation mechanism in Cu2S-based photovoltaics. Furthermore, through preliminary efforts to control oxygen incorporation at the interface, a more stable and efficient Cu2S-based solar cell may be envisioned.