Stability of 2D and quasi-2D perovskite materials and devices

3D perovskites are widely researched for their use in optoelectronic devices, yet suffer from issues with environmental stability. Here, the improved stability of 2D and quasi-2D perovskites under a range of environmental factors, as compared to their 3D counterparts, is discussed. Different 2D and quasi-2D perovskite materials have demonstrated significant improvements in the device stability compared to 3D perovskites due to their increased hydrophobicity and suppressed ion migration. However, fundamental investigations of these materials have been scarce and consequently detailed understanding of the processes responsible for experimental phenomena are often lacking despite huge interest in these materials. Even more importantly, there have been a limited number of structure-property studies for different material compositions, and research is generally by trial and error rather than by design. Here we discuss different stability issues in these materials and identify questions which need to be answered to design materials with further stability improvements.