Perovskite Photovoltaic Module Curvature from Lamination Correlates to Operational Stability

We report on a rapid, nondestructive scanning laser curvature method for directly characterizing an important and unacknowledged factor that can contribute to the stability of encapsulated single-junction and tandem perovskite solar modules, i.e., the curvature from lamination. The ability to directly identify mechanical stresses and their evolution in fully packaged modules provides critical information regarding possible risks for accelerated degradation and failure. We define a metric for the curvature relating the magnitude and variance in front-glass z-displacement to the “flatness” of the module. We also study the effects of package design and lamination parameters—specifically, encapsulant volume, module layout, front- and back-glass thickness, and ribbon placement with the goal of reducing the curvature and the resulting mechanical stress imposed after lamination. Critically, we show that flatter modules show significantly enhanced durability when compared to curved modules, increasing T₈₀ by about a factor of 2 from ≈900 to 1800 h under ISOS-L2 conditions at 65 °C. A direct link between mechanical stress imparted from lamination and chemical degradation mechanisms in modules provides an important design guideline to the community toward robust and reliable perovskite module manufacturing.