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

TLDR

Two‑dimensional hybrid perovskites are promising solar‑cell absorbers, offering a larger bandgap suitable for tandem devices, while the commonly used 3D perovskite (MA)[PbI3] suffers from moisture instability that necessitates anhydrous processing. The layered structure enables high‑quality spin‑coated films without the need for high‑temperature annealing. Devices using the layered (PEA)₂(MA)₂[Pb₃I₁₀] absorber achieve an open‑circuit voltage of 1.18 V and a 4.73 % power‑conversion efficiency, exhibit superior moisture resistance compared to the 3D perovskite, and provide greater molecular tunability for optimization.

Abstract

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.