2021/10/21 by Sarthak Jariwala, Jariwala, Sarthak, Rishi Kumar +11
Chemistry · Engineering · Materials Science · Physics and Astronomy · #Analytical Chemistry (journal) #Applied Physics (physics.app-ph) #Band gap #Chalcogenide Semiconductor Thin Films #Chemical engineering #Chemistry #Crystallography #FOS: Physical sciences #Formamidinium #Halide #Inorganic chemistry #Ion #Materials Science (cond-mat.mtrl-sci) #Materials science #Optoelectronics #Organic chemistry #Perovskite (structure) #Perovskite Materials and Applications #Quantum Dots Synthesis And Properties #Secondary ion mass spectrometry #Semiconductor Quantum Structures and Devices #Solid-state spectroscopy and crystallography #cond-mat.mtrl-sci #physics.app-ph
paper · pdf · doi:10.48550/arxiv.2110.11458
arxiv created 2021/10/21 · openalex publication_date 2021/10/21 · arxiv updated 2021/10/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Adding a large A-site cation, such as dimethylammonium (DMA), to the\nperovskite growth solution has been shown to improve performance and long-term\noperational stability of halide perovskite solar cells. To better understand\nthe origins of these improvements, we explore the changes in film structure,\ncomposition, and optical properties of a formamidinium (FA), Cs, Pb, mixed\nhalide perovskite following addition of DMA to the perovskite growth solution\nin the ratio DMA0.1FA0.6Cs0.3Pb(I0.8Br0.2)3. Using time-of-flight secondary-ion\nmass spectrometry (TOF-SIMS) we show that DMA is indeed incorporated into the\nperovskite, with a higher DMA concentration at the surface. Using a combination\nof PL microscopy and photo-induced force microscopy-based (PiFM) nanoinfrared\n(nanoIR), we demonstrate that incorporating DMA into the film leads to\nincreased local heterogeneity in the local bandgap, and clustering of the local\nformamidinium (CH5N2+) composition. In addition, using nano-X-ray diffraction,\nwe demonstrate that DMA incorporation also alters the local structural\ncomposition by changing the local d-spacing distribution and grain size. Our\nresults suggest that compositional variations in the organic cations at the\nA-site drive the structural heterogeneity observed in case of DMA incorporated\nfilms. Our results also suggest that while current-DMA-additive based\napproaches do have benefits to operational stability and device performance,\nprocess optimization to achieve local compositional and structural homogeneity\ncould further boost both of these gains in performance, bringing further gains\nto solar cells using DMA additives.\n