Earth-abundant thin films

Solar cells with thin-film absorbers require 100x less active-layer material than crystalline silicon, enabling low costs and potential for roll-to-roll fabrication. While traditional thin-film materials (cadmium telluride and copper indium gallium diselenide) rely on scarce or toxic species, “Earth-abundant” alternative materials have rarely demonstrated efficiencies far above 10%. Demonstrating a stable, readily manufacturable, Earth-abundant thin-film material with efficiency potential approaching 20% could be a game-changing development.

Innovations: To accelerate the efficiency enhancement of Earth-abundant thin films, including tin sulfide (SnS) and cuprous oxide (Cu2O), we are applying a structured defect-mitigation framework inspired by our experience with crystalline silicon technology. Taking a rational approach to improving the bulk and interface quality, we have demonstrated meaningful efficiency enhancements in both material classes[1]. This work suggests that many alternative PV materials are not fundamentally limited by a law of physics, but rather, by limited engineering investments.

[1] Y.S. Lee et al., Energy & Environmental Science 6, 2112-2118 (2013)P. Sinsermsuksakul et al., Applied Physics Letters 102, 053901 (2013).