Large-Grain Double Cation Perovskites with 18 μs Lifetime and High Luminescence Yield for Efficient Inverted Perovskite Solar Cells

• Published in: ACS energy letters Vol. 6; no. 3; pp. 1045 - 1054
• Main Authors: Gutierrez-Partida, Emilio, Hempel, Hannes, Caicedo-Dávila, Sebastián, Raoufi, Meysam, Peña-Camargo, Francisco, Grischek, Max, Gunder, René, Diekmann, Jonas, Caprioglio, Pietro, Brinkmann, Kai O, Köbler, Hans, Albrecht, Steve, Riedl, Thomas, Abate, Antonio, Abou-Ras, Daniel, Unold, Thomas, Neher, Dieter, Stolterfoht, Martin
• Format: Journal Article
• Language: English
• Published: American Chemical Society 12.03.2021
• ISSN: 2380-8195; 2380-8195
• DOI: 10.1021/acsenergylett.0c02642

Recent advancements in perovskite solar cell performance were achieved by stabilizing the α-phase of FAPbI3 in nip-type architectures. However, these advancements could not be directly translated to pin-type devices. Here, we fabricated a high-quality double cation perovskite (MA0.07FA0.93PbI3) with low bandgap energy (1.54 eV) using a two-step approach on a standard polymer (PTAA). The perovskite films exhibit large grains (∼1 μm), high external photoluminescence quantum yields of 20%, and outstanding Shockley–Read–Hall carrier lifetimes of 18.2 μs without further passivation. The exceptional optoelectronic quality of the neat material was translated into efficient pin-type cells (up to 22.5%) with improved stability under illumination. The low-gap cells stand out by their high fill factor (∼83%) due to reduced charge transport losses and short-circuit currents >24 mA cm–2. Using intensity-dependent quasi-Fermi level splitting measurements, we quantify an implied efficiency of 28.4% in the neat material, which can be realized by minimizing interfacial recombination and optical losses.