The formation of a homogeneous passivation layer based on phase-pure two-dimensional (2D) perovskites is a challenge for perovskite solar cells, especially when upscaling the devices to modules. Researchers from China's Wuhan University of Technology, Xidian University, University of Electronic Science and Technology of China and Germany's Technical University of Munich have revealed a chain-length-dependent and halide-related phase separation problem of 2D perovskite growing on top of three-dimensional perovskites.
The scientists have demonstrated that a homogeneous 2D perovskite passivation layer can be formed upon treatment of the perovskite layer with formamidinium bromide in long-chain ( >10) alkylamine ligand salts.
They achieved champion active-area efficiencies of 25.61%, 24.62% and 23.60% for antisolvent-free processed small- (0.14 cm2) and large-size (1.04 cm2) devices and mini-modules (13.44 cm2), respectively.
This passivation strategy is reportedly compatible with printing technology, enabling champion aperture-area efficiencies of 18.90% and 17.59% for fully slot-die printed large solar modules with areas of 310 cm2 and 802 cm2, respectively, demonstrating the feasibility of the upscaling manufacturing.
