Synergistic effect of additives on 2D perovskite film towards efficient and stable solar cell

Recently, two-dimensional (2D) organic-inorganic hybrid perovskites have attracted tremendous attention due to their excellent environment stability. However, the inhibition of out-of-plane charge transport limits the performance of 2D based perovskite solar cells (PVSCs). To overcome this issue, we prepare the vertical-orientated 2D perovskite film via introducing dimethyl sulfoxide (DMSO) and thio-semicarbazide (TSC) as additives into the precursor solution. High-quality 2D (BA)₂(MA)₃Pb₄I₁₃ (BA = n-butylammonium, MA = methylammonium) films with uniform morphology, increased grain size, intensified crystallinity and vertical orientation are therefore fabricated by a synergistic effect of additives. As a result, the trap-state density in 2D (BA)₂(MA)₃Pb₄I₁₃ films is reduced and the charge transport is remarkably improved. The power conversion efficiency (PCE) of the PVSCs is boosted from the 1.05% to 14.15%. An unsealed device retains 90.3% of its initial PCE after 720 h storage in air atmosphere with relative humidity of 25 ± 5% at 25 °C. The results show the synergistic effect of TSC and DMSO on perovskite films is an effective approach toward efficient and stable 2D PVSC.