ZrO₂/TiO₂ Electron Collection Layer for Efficient Meso-Superstructured\nHybrid Perovskite Solar Cells

Abstract

Since\nthe first reports of efficient organic–inorganic perovskite\nsolar cells in 2012, an explosion of research activity has emerged\naround the world, which has led to a rise in the power conversion\nefficiencies (PCEs) to over 20%. Despite the impressive efficiency,\na key area of the device which remains suboptimal is the electron\nextraction layer and its interface with the photoactive perovskite.\nHere, we implement an electron collection “bilayer”\ncomposed of a thin layer of zirconia coated with titania, sitting\nupon the transparent conductive oxide fluorine-doped tin oxide (FTO).\nWith this double collection layer we have reached up to 17.9% power\nconversion efficiency, delivering a stabilized power output (SPO)\nof 17.0%, measured under simulated AM 1.5 sunlight of 100 mW cm^–2 irradiance. Finally, we propose a mechanism of the\ncharge transfer processes within the fabricated architectures in order\nto explain the obtained performance of the devices.