Life cycle assessment of high-performance monocrystalline titanium dioxide nanorod-based perovskite solar cells

There is considerable research effort being made to improve the efficiency of solar cells. Perovskite architectures that use titanium dioxide nanorods as electron transport layers are among technologies that have been proven to have enhanced efficiency. However, assessments of the life cycle environmental performances of such nanorodbased perovskite solar cells are limited. In this study, a cradle-to-grave life cycle assessment is conducted to evaluate the environmental footprints in terms of energy payback time, greenhouse gas (GHG) emissions, and the net energy ratio of this architecture. Unlike most studies that focus on the life cycle of the cell processing, this study extends the scope to include the balance of the system (BOS) and to evaluate the environmental effects of reusing important components such as fluorine-doped tin oxide glass and the gold layer, which appear to significantly impact energy consumption and associated GHG emissions. The energy payback time is calculated to be 0.97(-0.41)(+0.78) years and the life cycle GHG emissions to be 181.5(-82)(+170) g CO2 eq/kWh of electricity produced for a solar system. The net energy ratio is 3.1, indicating the system is a net energy generator. The assembly life cycle stage, comprising the panel production, BOS and mounting of solar panels, generates the most GHG emissions and the contribution from the cell fabrication stage is second. It was observed that the embodied GHG emissions for fluorine-doped tin oxide glass and gold contribute just 4% of the total GHG emissions associated with the perovskite solar cell for a three-time reuse case.