What Is Limiting Pyrite Solar Cell Performance?

摘要

Iron pyrite (FeS_2), an earth-abundant transition metal di-chalcogenide (TMD), has exotic electronic and optical properties suitable for solar cell applications. For example, it has an indirect band gap at ～0.95 eV and a direct band gap at 1.05-1.10 eV that is comparable to Si (1.1 eV), while absorption coefficient of FeS_2 is almost two orders of magnitudes higher than that of Si.1 Like Si, FeS_2 solar cells also could have almost same theoretical energy conversion efficiency up to Shockley-Queisser limit. Additionally, the high absorption coefficient of FeS_2 offers the opportunities to fabricate a very thin absorber layer of thickness < 20 nm, which so far does not seem possible with other thin-film solar cell materials. It infers a sharp reduction of the production cost (⊄/W) of electricity due to reduction of material cost. Consequently, FeS_2 has gained interest as a potential non-toxic super absorber material in lieu of widely used but toxic and rare element containing CdTe and Cu(ln, Ga)Se_2 for thin-film solar cells.