Metal-Halide Perovskite Design for Next-Generation Memories: First-Principles Screening and Experimental Verification

Memory devices have been advanced so much, but still it is highly required to find stable and reliable materials with low-power consumption. Halide perovskites (HPs) have been recently adopted for memory application since they have advantages of fast switching based on ionic motion in crystal structure. However, HPs also suffer from poor stability, so it is necessary to improve the stability of HPs. In this regard, combined first-principles screening and experimental verification are performed to design HPs that have high environmental stability and low-operating voltage for memory devices. First-principles screening identifies 2D layered AB₂X₅ structure as the best candidate switching layer for memory devices, because it has lower formation energy and defect formation energy than 3D ABX₃ or other layered structures (A₃B₂X₇, A₂BX₄). To verify results, all-inorganic 2D layered CsPb₂Br₅ is synthesized and used in memory devices. The memory devices that use CsPb₂Br₅ show much better stability and lower operating voltages than devices that use CsPbBr₃. These findings are expected to provide new opportunity to design materials for reliable device applications based on calculation, screening, and experimental verification.