Geoffroy Hautier1
Dartmouth College1
Thin film photovoltaic technology has advantages to single-crystal silicon in terms of flexibility, lower energy manufacturing needs or potential for tandem cells. However, the high efficiency technologies available (e.g., CIGS, CdTe or halide perovksites) have all issues in terms of cost, abundance or long-term stability. Finding new solar absorber is a cumbersome process involving complex synthesis and characterization. First principles computations on the other hand offers an attractive way to speed up this process. Here, we will report on a large scale high-throughput computational search for new solar absorbers among known inorganic materials. Importantly, the need for high carrier lifetime is taken into account by considering in the screening intrinsic defects and their role as potential Shockley-Read-Hall recombination centers. Screening 30,000 known inorganic compounds, we identify a handful very promising solar absorbers combing large optical absorption in the visible, good transport properties and high carrier lifetime. I will discuss the chemistries that we found and highlight a few interesting new materials. I will especially focus on BaCd2P2, a new phosphide where our experimental follow-up work confirms the promising properties including adequate band gap but also long carrier lifetime. We also show that this new material is extremely stable even in harsh conditions. I will finish my talk by discussing how large data sets of defect computations can also be used to test and develop design principles for solar absorbers with “defect-tolerance”.