Orientation Regulation of Phenylethylammonium Cation Based 2D Perovskite Solar Cell with Efficiency Higher Than 11%

Abstract

Increasing the power conversion efficiency (PCE) of the two‐dimensional (2D) perovskite‐based solar cells (PVSCs) is really a challenge. Vertical orientation of the 2D perovskite film is an efficient strategy to elevate the PCE. In this work, vertically orientated highly crystalline 2D (PEA)2(MA)n–1PbnI3n+1 (PEA= phenylethylammonium, MA = methylammonium, n = 3, 4, 5) films are fabricated with the assistance of an ammonium thiocyanate (NH4SCN) additive by a one‐step spin‐coating method. Planar‐structured PVSCs with the device structure of indium tin oxide (ITO)/poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate)/(PEA)2(MA)n–1PbnI3n+1/[6,6]‐phenyl‐C61‐butyric acid methyl ester/bahocuproine/Ag are fabricated. The PCE of the PVSCs is boosted from the original 0.56% (without NH4SCN) to 11.01% with the optimized NH4SCN addition at n = 5, which is among the highest PCE values for the low‐n (n < 10) 2D perovskite‐based PVSCs. The improved performance is attributed to the vertically orientated highly crystalline 2D perovskite thin films as well as the balanced electron/hole transportation. The humidity stability of this oriented 2D perovskite thin film is also confirmed by the almost unchanged X‐ray diffraction patterns after 28 d exposed to the moisture in a humidity‐controlled cabinet (Hr = 55 ± 5%). The unsealed device retains 78.5% of its original PCE after 160 h storage in air atmosphere with humidity of 55 ± 5%. The results provide an effective approach toward a highly efficient and stable PVSC for future commercialization.

Highly Efficient Guanidinium‐Based Quasi 2D Perovskite Solar Cells via a Two‐Step Post‐Treatment Process

“…These results demonstrate that more efficient charge transfer is achieved by the compact and well‐aligned crystal grains formed upon GASCN post‐treatment, which further explains the observed increase of J sc (see Figure c). The reason why the 6 GASCN sample presents the most obvious PL quenching and shortest PL lifetime could be attributed to its largest grain size (see Figure ), which dominates the quenching effect and the charge transfer from GASCN treated perovskite film to HTL layer …”

“…More recently, 2D Ruddlesden–Popper (RP) perovskites have emerged as alternative materials which provided a noticeable structural flexibility and improved long‐term stability compared with 3D perovskites. The PCE of 2D PVSCs has gradually increased to over 15% . Besides the 2D RP perovskite, a Dion–Jacobson type of perovskites has also been utilized to fabricate 2D PVSCs with a maximum PCE of 13% …”

Interface Engineering in n‐i‐p Metal Halide Perovskite Solar Cells

“…Existing “edge states” may provide a direct pathway for dissociating excitons into longer‐lived free carriers. Third, the structure and properties can be easily adjusted by incorporating spacer cations with various alkyl chain length and ammonium species . Thin 2D MHP films can be introduced at either ETL/MHP or MHP/HTL interfaces to construct 2D/3D bilayer MHP solar cells.…”

Black Phosphorus Quantum Dots Induced High‐Quality Perovskite Film for Efficient and Thermally Stable Planar Perovskite Solar Cells

“…To acquire high‐quality perovskite films, researchers have developed a number of preparation strategies. Among these, the additive‐assisted growth method has been widely exploited and shown to be effective . For example, Liu and co‐workers have introduced semiconducting molecules with Lewis acid or base functional groups into the perovskite absorber, leading to an improved PCE of 19.3% and better environmental stability .…”