Life cycle assessment of hole transport free planar-mesoscopic perovskite solar cells

Abstract

Organo-metal lead halide perovskite solar cells (PSCs) attract attention due to their low cost and high power conversion efficiency. Some weak points of this technology are short lifetime, instability, and expensive metal electrode deposition. Eliminating the unstable hole transport layer (HTL) and using carbon-based materials as the counter electrode would address both. In this work, we present a cradle-to-gate life cycle assessment of two HTL-free PSC designs, which use solution phase deposition to achieve mesoscopic and planar structures. Environmental impacts of producing 1 m(2) PSCs are converted to impacts per kWh electricity generation assuming 5years of operational lifetime. We find that major impacts come from fluorine doped tin oxide (FTO) glass patterning due to the electricity consumption of FTO patterning and glass cleaning processes. Even though the electricity consumption when manufacturing both PSCs is similar, their different efficiencies make the environmental impacts per kWh of electricity higher for the mesoscopic PSC than for the planar PSC. Energy payback time values of planar PSCs and mesoscopic PSCs are 0.58 and 0.74years, respectively, and these values are shorter than those of commercial first and second generation solar cells. However, the global warming potential (GWP) values of planar and mesoscopic PSCs are 75 and 94g CO2-eq/kWh, respectively, and these values are still higher than those of commercial solar cells. To reach the GWP of commercial cells, the operational lifetime would have to be 8 and 10years for planar and mesoscopic PSCs, respectively.