2D-Quasi-2D-3D Hierarchy Structure for Tin Perovskite Solar Cells with Enhanced Efficiency and Stability

Abstract

Development of tin halide perovskites is limited by the extremely poor stability and high background carrier density. Here, based on a pseudohalogen ''catalyst,'' we fabricated a Sn-based hierarchy structure perovskite in a one-step process, comprising highly parallel-orientation 2D PEA 2 SnI 4 on the surface of 3D FASnI 3 . The hierarchy structure delivers significantly enhanced stability and oxidation resistance in air atmosphere. We then explored hierarchy structure perovskite films in planar structure solar cells and achieved a PCE up to 9.41%. HIGHLIGHTS 2D-quasi-2D-3D hierarchy structure perovskite is fabricated for the first time Removable pseudohalogen acts as a regulator to manipulate tin perovskite structureThe hierarchy structure effectively resists oxidation and increases carrier mobilityThe hierarchy structure tin perovskite solar cells achieve a record PCE of 9.41% Wang et al., Joule SUMMARYThe power conversion efficiency (PCE) of tin perovskite solar cells is impeded by the extremely poor resistance to oxidation and high density of intrinsic Sn vacancies. Herein, we grow a 2D-quasi-2D-3D Sn perovskite film using removable pseudohalogen NH 4 SCN as a structure regulator. This hierarchy structure remarkably enhances air stability resulting from the parallel growth of 2D PEA 2 SnI 4 as the surface layer. We then explore the hierarchy structure perovskite films in planar structural solar cells, which generate a PCE up to 9.41%. The device retains 90% of its initial performance for almost 600 hr. Our results suggest that adding removable NH 4 SCN in a perovskite precursor can significantly improve the stability and photovoltaic performance of Sn perovskite. This finding provides a powerful strategy to manipulate the structure of low-dimensional perovskite in order to enhance the performance of perovskite solar cells.

Efficient and Stable FASnI3 Perovskite Solar Cells with Effective Interface Modulation by Low‐Dimensional Perovskite Layer

“…[9,30] Figure 5d shows the photoluminescence( PL) spectra of FASnI 3 films on ag lass substrate without and with PEABr treatment. [42][43][44] Based on the resultso fU PS and UV/Vis, an energy-level diagram for the inverted planar PSCs containing the FASnI 3 without and with PEABr treatment was constructed in Figure 6a. [9,30] When the low-dimensional ultrathin film was introduced after PEABr treatment, the film had a stronger PL intensity with ac lear blueshift to approximately 885 nm, whichc an be attributed to the enhanced crystallinity and band-gap increaseb yi ncorporation of Br and the formation of the low-dimensional PEA-based perovskite phase with larger band gap.…”

“…[20] To date, there have been considerable efforts to suppress the oxidation of Sn 2 + in tin halide perovskites, resulting in the improved performance of tin-based PSCs. [43,44] However,i ti s not easy to modulate or control the blended 2D/3D tin halide perovskite phases in the applicable process. [42] So far,PEAI-incorporated tin halide PSCs have achieved ad evice conversion efficiency of over 9%.…”

“…Extra peaks emerged in the XRD patterns of the films treated with 6a nd 10 mg mL À1 PEABr solution, which could be ascribed to the diffraction peaks from the lowdimensional perovskites with the various PEABr contents, consistent with the previous report. [42][43][44] As we know,asmooth and compactp erovskite film is ap rerequisite for high-performance devices. The superficialu ltrathin lowdimensional perovskite benefits the band-level alignment between FASnI 3 and PCBM, leadingt oe lectron transport enhancement at the interface.…”

Combining Efficiency and Stability in Mixed Tin–Lead Perovskite Solar Cells by Capping Grains with an Ultrathin 2D Layer

“…We then acquired grazing‐incidence wide‐angle X‐ray scattering (GIWAXS) data to characterize the structure of perovskites. The incidence angle was set as low as 0.5° to probe the surface structure 28. As shown in Figure 2c and Figure S5a (Supporting Information), the main diffraction peaks from the pristine perovskite film are assigned to the polycrystalline 3D perovskite 29.…”

Interlayer Cross‐Linked 2D Perovskite Solar Cell with Uniform Phase Distribution and Increased Exciton Coupling

“…RP phase 2D perovskites are attractive for several reasons: First, the solution‐processed 2D perovskite film exhibits the unique multicomponent quantum wells (MQW) structure that could naturally confine excitons, showing their enormous potential in light emitting diode (LED) applications . Second, the orientation of 2D slices could be altered perpendicular to the substrates to facilitate charge collection efficiency with many methods, such as hot‐casting NH 4 SCN or NH 4 Cl additive assisting . Third, the humidity stability of perovskite could be significantly improved due to the hydrophobic property of insulating ligands, paving the way to the long‐time operation of perovskite solar cells (PSCs) .…”