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)(2)NH3+, MA=CH3NH3+) show an open-circuit voltage of 1.18V 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 3Dperovskite (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 2Dstructure 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.