A life cycle assessment of perovskite/silicon tandem solar cells

• Published in: Progress in photovoltaics 2017-08, Vol.25 (8), p.679-695
• Main Authors: Monteiro Lunardi, Marina, Wing Yi Ho‐Baillie, Anita, Alvarez‐Gaitan, Juan Pablo, Moore, Stephen, Corkish, Richard
• Format: Article
• Language: English
• Subjects: Aluminum; Avoidance; Cost engineering; Electric contacts; Electrical resistivity; Electrodes; Energy consumption; Environmental impact; environmental impacts; Eutrophication; Global warming; Gold; Indium tin oxides; LCA; Life cycle assessment; Life cycle engineering; Life cycles; Noble metals; P-n junctions; Photovoltaic cells; Silicon; Silver; Solar cells; tandem solar cells; Technology assessment; Toxicity
• ISSN: 1062-7995; 1099-159X
• DOI: 10.1002/pip.2877

Given the rapid progress in perovskite solar cells in recent years, perovskite/silicon (Si) tandem structure has been proposed to be a potentially cost‐effective improvement on Si solar cells because of its higher efficiency at a minimal additional cost. As part of the evaluation, it is important to conduct a life cycle assessment on such technology in order to guide research efforts towards cell designs with minimum environmental impacts. Here, we carry out a life cycle assessment to assess global warming, human toxicity, freshwater eutrophication and ecotoxicity and abiotic depletion potential impacts and energy payback time associated with three perovskite/Si tandem cell structures using silver (Ag), gold (Au) and aluminium (Al) as top electrodes compared with p–n junction and hetero‐junction with intrinsic inverted layer Si solar cells. It was found that the replacement of the metal electrode with indium tin oxide/metal grid in the tandem cell reduces the environmental impacts significantly compared with the perovskite cell. For all the impacts assessed, we conclude that the perovskite/Si tandem using Al as top electrode has better environmental outcomes, including energy payback time, when compared with the other tandem structures studied. Use of Al in preference to noble metals for contacts, Si p–n junction in preference to intrinsic inverted layer and the avoidance of 2,20,7,70‐tetrakis(N,N‐di‐p‐methoxyphenylamine)9,90‐spirobifluorene (Spiro‐OMeTAD) are environmentally beneficial. The key result found of this work is that the most important factor for the better environmental impacts of these tandem solar cells is the transparency and electrical conductivity of the perovskite layer after it fails. Copyright © 2017 John Wiley & Sons, Ltd. We carry out a life cycle assessment to assess environmental impacts and energy payback time associated with three perovskite/Si tandem structures. For all the impacts assessed, we conclude that the tandem using Al as top electrode in preference to noble metals, Si p–n junction in preference to intrinsic inverted layer and the avoidance of Spiro‐OMeTAD are environmentally beneficial. Better environmental impacts are possible if perovskite materials become transparent and electrically conductive when they fail.