Toward Stable Perovskite Solar Cell Architectures: Robustness Against Temperature Variations of Real-World Conditions

Perovskite solar cells (PSCs) are among the most promising emerging photovoltaic technologies, demonstrating power conversion efficiencies (PCEs) close to 24%. The major challenge hampering commercialization of this technology is the low stability toward inevitable stress factors of PV modules such as temperature variations. Temperature variations are reported to induce a decline in photocurrent of up to 80%, depending on the device architecture, the charge transport layers, and the perovskite absorber material. The effect is particularly pronounced in methylammonium lead iodide-based PSCs, with TiO2 as the electron transport layer (ETL) and spiro-MeOTAD as the hole transport layer (HTL). This article reports on three different strategies to overcome the temperature-variation-induced degradation by altering the interfaces. The charge selective transport layers, the perovskite absorber layer composition, and the perovskite deposition technique are varied. We find that the interface between the ETL and the perovskite layer is the key to temperature-variation-induced degradation. We demonstrate stable PSCs with regard to temperature variations with PCEs as high as 19.5%. Finally, the relevance of the temperature-variation-induced degradation for outdoor applications is shown by stressing PSCs with real outdoor temperature profiles (between 21 and 75 degrees C).