Lamination for Long-term Stability of Perovskite Solar Cells

Tesis Energía y Ambiente (maestría) - Instituto Tecnológico de Buenos Aires, Buenos Aires - Karlsruher Institut für Technologie, Karlsruhe, 2021 The climate change and the constantly rising demand of energy worldwide requires the development of efficient, though environment-friendly, systems to generate renewable power. The use of perovskite solar cells in photovoltaic applications has proven to be a promising approach facing this task. The main issue preventing commercialization of this new technology is the instability of the perovskite material when exposed to moisture, oxygen, and elevated temperatures. This work aims to face this concern by improving encapsulation of perovskite solar cells with a glass-to-glass encapsulation method, using butyl rubber as edge sealant and polyolefin as encapsulant. Furthermore, this encapsulation technique is applied to perovskite solar modules. High temperatures usually required for encapsulation is optimized for CsFAPbI3 and MAPbI3 based solar cells and modules, so that power conversion efficiency does not decrease after lamination. The quality of the encapsulation is tested at 85 % relative humidity and 25 °C wherein devices encapsulated at 85 °C reach 80 % of their initial efficiency after approximately 550 h. A rapid decrease in performance of encapsulated perovskite cells under constant illumination and biased is attributed to the Ag electrode. In contrast, devices with Au electrode are stable for 62 h. Further optimization of the encapsulation method by using the transparent conducting oxide layer as conductive path through the encapsulation increases device stability. This is shown by comparing different contacting methods with an electrical calcium test. Applying and testing this contacting method to the encapsulation of perovskite cells and modules is a task for future research.