A Layered Hybrid Perovskite Solar-Cell Absorber with Enhanced Moisture Stability

Two‐dimensional hybrid perovskites are used as absorbers in solar cells. Our first‐generation devices containing (PEA)2(MA)2[Pb3I10] (1; PEA=C6H5(CH2)2NH3+, MA=CH3NH3+) show an open‐circuit voltage of 1.18 V and a power conversion efficiency of 4.73 %. The layered structure allows for high‐quality films to be deposited through spin coating and high‐temperature annealing is not required for device fabrication. The 3D perovskite (MA)[PbI3] (2) has recently been identified as a promising absorber for solar cells. However, its instability to moisture requires anhydrous processing and operating conditions. Films of 1 are more moisture resistant than films of 2 and devices containing 1 can be fabricated under ambient humidity levels. The larger bandgap of the 2D structure is also suitable as the higher bandgap absorber in a dual‐absorber tandem device. Compared to 2, the layered perovskite structure may offer greater tunability at the molecular level for material optimization. 2D Pb–I perovskites (see figure) are used as absorbers in solar cells with an open‐circuit voltage of 1.18 V and a power conversion efficiency of 4.73 %. Although its 3D analogue is a promising solar‐cell absorber, its instability to moisture requires anhydrous processing. 2D perovskites are more moisture resistant and devices can be fabricated in humid conditions. They may offer greater tunability at the molecular level for material optimization.