  Thin-film photovoltaics offers a path to significantly decarbonize our energy
production. Unfortunately, current materials commercialized or under
development as thin-film solar cell absorbers are far from optimal as they show
either low power conversion efficiency or issues with earth-abundance and
stability. Entirely new and disruptive materials platforms are rarely
discovered as the search for new solar absorbers is traditionally slow and
serendipitous. Here, we use first principles high-throughput screening to
accelerate this process. We identify new solar absorbers among known inorganic
compounds using considerations on band gap, carrier transport, optical
absorption but also on intrinsic defects which can strongly limit the carrier
lifetime and ultimately the solar cell efficiency. Screening about 40,000
materials, we discover the Zintl-phosphide BaCd$_{2}$P$_{2}$ as a potential
high-efficiency solar absorber. Follow-up experimental work confirms the
predicted promises of BaCd$_{2}$P$_{2}$ highlighting an optimal band gap for
visible absorption, bright photoluminescence, and long carrier lifetime of up
to 30 ns even for unoptimized powder samples. Importantly, BaCd$_{2}$P$_{2}$
does not contain any critical elements and is highly stable in air and water.
Our work opens an avenue for a new family of stable, earth-abundant,
high-performance Zintl-based solar absorbers. It also demonstrates how recent
advances in first principles computation can accelerate the search of
photovoltaic materials by combining high-throughput screening with experiment.
