Science News: 2021 ACS Energy Letters (IF 19.05), PCE 23.46% & greater than 80% fill factor! Defect mitigation strategy!

　　In September 2021, ACS Energy Letters (IF 19.05)  journal published a study by Michael Grätzel from École polytechnique fédérale de Lausanne (EPFL) in Switzerland. The defects in metal halide perovskites are not conducive to the performance and stability of photovoltaic devices. Therefore, scholars pay much attention to the development of defect mitigation strategies.

　　In the study, the author reported a simple strategy to use methylammonium triiodide (MAI₃) as an additive to the perovskite precursor solution. In experiments through instruments such as solar simulators, as well as through X-ray diffraction, density functional theory calculations, molecular dynamics simulations, solid-state nuclear magnetic resonance, steady-state, time-resolved photoluminescence (TRPL), and time-resolved terahertz spectroscopy (TRTS) to examine the influence of MAI₃ on the structure and photoelectric properties. Specifically, TRPL and TRTS indicate that MAI₃ suppresses nonradiative recombination and increases the charge carrier mobility.

　　As a result, the champion device exhibited a power conversion efficiency (PCE) of 23.46% with a high fill factor greater than 80%. In addition, these devices exhibit enhanced operational stability. The best performing device can maintain about 90% of its initial PCE under 1 sun illumination a with maximum power point tracking for 350 h.