Discovery of the Zintl-phosphide BaCd₂P₂ as a long carrier lifetime and stable solar absorber

Thin-film photovoltaics (PV) offers a path to decarbonize global energy production. Unfortunately, existing thin-film solar absorbers have major issues associated with either elemental abundance, stability, or performance. Entirely new and disruptive materials platforms are rarely discovered, and their search is traditionally slow and serendipitous. Here, we report a first-principles high-throughput (HT) computational screening for new solar absorbers among 40,000 known inorganic materials. Next to band gap and carrier effective masses, we also use computed intrinsic defects as they can limit the carrier lifetime. We identify the Zintl-phosphide BaCd₂P₂ as a potential high-efficiency solar absorber. Follow-up experiments confirm the promises of BaCd₂P₂, highlighting an optimal band gap, bright photoluminescence (PL), and long carrier lifetime, even in unoptimized powder samples. Importantly, BaCd₂P₂ contains no critical elements and is stable in air and water. Our work demonstrates how computational screening combined with experiments can accelerate the search for photovoltaic materials.