title: Can Carbon Nanomaterials Improve CZTS Photovoltaic Devices? Evaluation of Performance and Impacts Using Integrated Life-Cycle Assessment and Decision Analysis.
abstract: In emergent photovoltaics, nanoscale materials hold promise for optimizing device characteristics; however, the related impacts remain uncertain, resulting in challenges to decisions on strategic investment in technology innovation. We integrate multi-criteria decision analysis (MCDA) and life-cycle assessment (LCA) results (LCA-MCDA) as a method of incorporating values of a hypothetical federal acquisition manager into the assessment of risks and benefits of emerging photovoltaic materials. Specifically, we compare adoption of copper zinc tin sulfide (CZTS) devices with molybdenum back contacts to alternative devices employing graphite or graphene instead of molybdenum. LCA impact results are interpreted alongside benefits of substitution including cost reductions and performance improvements through application of multi-attribute utility theory. To assess the role of uncertainty we apply Monte Carlo simulation and sensitivity analysis. We find that graphene or graphite back contacts outperform molybdenum under most scenarios and assumptions. The use of decision analysis clarifies potential advantages of adopting graphite as a back contact while emphasizing the importance of mitigating conventional impacts of graphene production processes if graphene is used in emerging CZTS devices. Our research further demonstrates that a combination of LCA and MCDA increases the usability of LCA in assessing product sustainability. In particular, this approach identifies the most influential assumptions and data gaps in the analysis and the areas in which either engineering controls or further data collection may be necessary.
authors.affiliation: Daniel J Evans School of Public Policy and Governance, University of Washington, Seattle, WA, USA.|Environmental Laboratory, Engineer Research and Development Center, U.S. Army Corps of Engineers, Concord, MA, USA.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Scott
authors.affiliation: Daniel J Evans School of Public Policy and Governance, University of Washington, Seattle, WA, USA.
authors.forename: Alison C
authors.initials: AC
authors.lastname: Cullen
authors.affiliation: Environmental Laboratory, Engineer Research and Development Center, U.S. Army Corps of Engineers, Concord, MA, USA.
authors.forename: Cate
authors.initials: C
authors.lastname: Fox-Lent
authors.affiliation: Environmental Laboratory, Engineer Research and Development Center, U.S. Army Corps of Engineers, Concord, MA, USA.
authors.forename: Igor
authors.initials: I
authors.lastname: Linkov
mesh_terms: D003198:Computer Simulation; D003247:Conservation of Natural Resources / Q000379:methods*; D003365:Costs and Cost Analysis; D003661:Decision Support Techniques; D004867:Equipment Design; D006108:Graphite / Q000737:chemistry; D008027:Light; D008889:Military Personnel; D008982:Molybdenum; D009010:Monte Carlo Method; D037742:Nanotubes, Carbon / Q000737:chemistry*; D018570:Risk Assessment; D035501:Uncertainty; D014481:United States
chemical_list: D037742:Nanotubes, Carbon; D006108:Graphite; D008982:Molybdenum
keywords: Emerging technologies; graphene; life-cycle impact assessment; multi-criteria decision analysis; nanotechnology