Methylammonium Triiodide for Defect Engineering of
High-Efficiency Perovskite Solar Cells

Alharbi, Essa A.; Krishna, Anurag; Baumeler, Thomas P.; Dankl, Mathias; Fish, George C.; Eickemeyer, Felix; Ouellette, Olivier; Ahlawat, Paramvir; Škorjanc, Viktor; John, Elsa; Yang, Bowen; Pfeifer, Lukas; Avalos, Claudia Esther; Pan, Linfeng; Mensi, Mounir; Schouwink, Pascal Alexander; Moser, Jacques-E.; Hagfeldt, Anders; Rothlisberger, Ursula; Zakeeruddin, Shaik M.; Grätzel, Michael

doi:10.1021/acsenergylett.1c01754.s001

nz1c01754_si_001.pdf (1.68 MB)

Methylammonium Triiodide for Defect Engineering of High-Efficiency Perovskite Solar Cells

journal contribution

posted on 2021-09-22, 19:03 authored by Essa A. Alharbi, Anurag Krishna, Thomas P. Baumeler, Mathias Dankl, George C. Fish, Felix Eickemeyer, Olivier Ouellette, Paramvir Ahlawat, Viktor Škorjanc, Elsa John, Bowen Yang, Lukas Pfeifer, Claudia Esther Avalos, Linfeng Pan, Mounir Mensi, Pascal Alexander Schouwink, Jacques-E. Moser, Anders Hagfeldt, Ursula Rothlisberger, Shaik M. Zakeeruddin, Michael Grätzel

The defects present in metal halide perovskite are deleterious to both the performance and stability of photovoltaic devices. Consequently, there is an intense focus on developing defect mitigation strategies. Herein we report a facile strategy that employs methylammonium triiodide (MAI₃) as an additive to the perovskite precursor solution. We examine the effect of MAI₃ on the structural and optoelectronic properties by 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). Specifically, TRPL and TRTS show that MAI₃ suppresses nonradiative recombination and increases the charge carrier mobility. As a result, the champion device shows a power conversion efficiency (PCE) of 23.46% with a high fill factor of >80%. Furthermore, these devices exhibit enhanced operational stability, with the best device retaining ∼90% of its initial PCE under 1 sun illumination with maximum power point tracking for 350 h.