Lead, tin, bismuth or organics: Assessment of potential environmental and human health hazards originating from mature perovskite PV technology

Perovskite solar cells (PSCs) represent a promising emerging photovoltaic technology, though its commercialization could be limited by toxicity of lead halides used as absorber materials. Lead replacement with other less toxic elements is actively discussed and intensively investigated in many research laboratories over the world. However, the comparative study of the toxicity/hazard effects induced by different metal halides (Pb, Sn, Bi), as well as organic counterparts of perovskites (i.e., methylammonium or formamidinium halides) is still missing. Herein, we present the first systematic in vitro and in vivo study of the acute toxicity effects of a panel of the precursors commonly applied in the fabrication of PSCs. Surprisingly, we found that bio-effects of methylammonium iodide (MAI) are similar to that of lead iodide (PbI2) in in vitro models. Furthermore, tin iodide (SnI2) is just about ten times less toxic than PbI2 which makes questionable its potential use as “eco-friendly” material. In vivo experiments demonstrated that MAI and formamidinium iodide (FAI) are three times more toxic than PbI2 in terms of the lethal dose 50% (LD50). Thus, the presented here results show that the high acute toxicity effects of organic halides were largely overlooked by the community in the shadow of the actively discussed lead toxicity. Still, the potential mass application of PSCs is not expected to cause significant environmental impact or health hazard in comparison with other sources of lead pollution associated with the common use of lead-acid batteries, lead-containing pigments, fuel additives, roofing and electronics soldering materials, lead glassware and even tobacco smoke.