From spin coating to roll-to-roll: investigating the challenge of upscaling lead halide perovskite solar cells

• Published in: IET renewable power generation 2017-04, Vol.11 (5), p.546-549
• Main Authors: Baker, Jennifer A, Mouhamad, Youmna, Hooper, Katherine E.A, Burkitt, Daniel, Geoghegan, Mark, Watson, Trystan M
• Format: Article
• Language: English
• Subjects: crystallisation; dimethylformamide solvent; evaporation; evaporation rate; fill factor improvement; film crystallisation; hot plate; K‐bar coated perovskite film airflow; K‐bar coating; lead compounds; lead halide perovskite solar cell upscaling; mixed lead halide precursor; nanometre thick film; PbCl2; PCE; perovskite precursor deposition; power conversion efficiency; rough film; semiempirical model; short‐circuit current improvement; short‐circuit currents; solar cells; Special Section: Selected Papers from the 12th Photovoltaic Science, Application and Technology Conference (PVSAT-12); spin coating; spin coating perovskite dynamics; thick film devices
• ISSN: 1752-1416; 1752-1424; 1752-1424
• DOI: 10.1049/iet-rpg.2016.0683

Spin coating, typically used to achieve nanometre thick films, is the established method for depositing perovskite precursors at lab scale for use in solar cells. This study investigates the dynamics of spin coating perovskite. By combining experimental measurement with a semi-empirical model the evaporation rate of the dimethylformamide solvent during the spin coating of a mixed lead halide precursor is determined to be 1.2 × 10–8 m/s. When K-bar coating the same precursor the solvent does not significantly evaporate during the deposition process and when this film is crystallised on a hot plate a rough film results which gives a power conversion efficiency (PCE) of less than 2%. By increasing the airflow of the K-bar coated perovskite film during crystallisation to 2.7 × 10–4 m/s the PCE increases significantly to 8.5% through an improvement in short-circuit current and fill factor.