https://www.sciencedaily.com/releases/2021/06/210622123238.htm > Resistive switching memory is a promising contender for next-generation memory device due to its advantages of simple structure and low power consumption. Various materials have been previously studied for resistive switching memory. Among them, halide perovskites are receiving much attention for use in the memory because of low operation voltage and high on/off ratio. However, halide perovskite-based memory devices have limitations of slow switching speed which hinder their practical application in memory devices. > To this, the researchers at POSTECH (Prof. Jang-Sik Lee, Prof. Donghwa Lee, Youngjun Park, and Seong Hun Kim) have successfully developed ultra-fast switching memory devices using halide perovskites by using a combined method of first-principles calculations and experimental verification. From a total of 696 compounds of halide perovskites candidates, Cs3Sb2I9 with a dimer structure was selected as the best candidate for memory application. To verify the calculation results, memory devices using the dimer-structured Cs3Sb2I9 were fabricated. They were then operated with an ultra-fast switching speed of 20 ns, which was more than 100 times faster than the memory devices that used the layer-structured Cs3Sb2I9. In addition, many of the perovskites contain lead (Pb) in the materials which has been raised as an issue. In this work, however, the use of lead-free perovskite eliminates such environmental problems.