All-perovskite tandem solar cells (Keynote Presentation)

We will present a universal close space annealing (CSA) strategy that increases grain size, enhances crystallinity, and prolongs carrier lifetimes in low-bandgap (~1.25 eV) and wide-bandgap (~1.75-1.80 eV) perovskite films. High-quality perovskite absorber layers are obtained with slowed solvent releasing process, enabling fabrication of efficient single-junction perovskite solar cells and all-perovskite tandem solar cells. We will also present a new self-assembly monolayer (SAM) material for efficient wide-bandgap perovskite subcells with a centimeter-scale area, leading to 26.4% certified record effciency of 1 cm2 all-perovskite tandem solar cells. We will also discuss the design and optimization of interconneting layers for all-perovskite tandems.