Perovskite seeding growth of formamidinium-lead-iodide-based perovskites for efficient and stable solar cells

• DOI: 10.1038/s41467-018-04029-7
• Publication Date: 2018-04-17T11:52:23Z
• Authors: Yicheng Zhao; Hairen Tan; Haifeng Yuan; Zhenyu Yang; James Z. Fan; Junghwan Kim; Oleksandr Voznyy; Xiwen Gong; Li Na Quan; Chih Shan Tan; Johan Hofkens; Dapeng Yu; Qing Zhao; Edward H. Sargent
• Keywords: Thin-Film Solar Cells; Science; Perovskite Solar Cell Technology; Materials Science; Photovoltaic Cells; Seeding; 02 engineering and technology; 7. Clean energy; Article; Engineering; Chemical engineering; Band gap; FOS: Electrical engineering, electronic engineering, information engineering; Materials Chemistry; Nanotechnology; Formamidinium; Electrical and Electronic Engineering; Optoelectronics; Applications of Quantum Dots in Nanotechnology; Perovskite (structure); FOS: Chemical engineering; Photovoltaic system; Iodide; FOS: Nanotechnology; Physics; Q; Materials science; Thin-Film Solar Cell Technology; Photovoltaics; Chemistry; Caesium; Solar Cell Efficiency; Electrical engineering; Physical Sciences; Thermodynamics; Perovskite Solar Cells; Crystallization; 0210 nano-technology; Inorganic chemistry

AbstractFormamidinium-lead-iodide (FAPbI3)-based perovskites with bandgap below 1.55 eV are of interest for photovoltaics in view of their close-to-ideal bandgap. Record-performance FAPbI3-based solar cells have relied on fabrication via the sequential-deposition method; however, these devices exhibit unstable output under illumination due to the difficulty of incorporating cesium cations (stabilizer) in sequentially deposited films. Here we devise a perovskite seeding method that efficiently incorporates cesium and beneficially modulates perovskite crystallization. First, perovskite seed crystals are embedded in the PbI2 film. The perovskite seeds serve as cesium sources and act as nuclei to facilitate crystallization during the formation of perovskite. Perovskite films with perovskite seeding growth exhibit a lowered trap density, and the resulting planar solar cells achieve stabilized efficiency of 21.5% with a high open-circuit voltage of 1.13 V and a fill factor that exceeds 80%. The Cs-containing FAPbI3-based devices show a striking improvement in operational stability and retain 60% of their initial efficiency after 140 h operation under one sun illumination.