“…Layered perovskites can be classified as Ruddlesden–Popper, Dion–Jacobson and Aurivillius structures. The last two are mostly represented by materials with photocatalytic [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ], ferroelectric [ 54 , 55 , 56 , 57 , 58 ] and luminescent [ 59 , 60 , 61 , 62 , 63 ] properties. In this paper, we focused on the proton-conducing layered perovskites with a Ruddlesden-Popper structure, which represent a large novel class of proton-conducting materials.…”