Engineering of A-site cations in APbI3 (A = Cs, Rb, K) perovskites for resistive switching control and self-rectifying memristors for next-generation computing applications

Abstract

The resistive switching in memristor devices is highly influenced by structural and electronic properties, which can be tailored through material composition. Unlike optoelectronic devices, lattice distortion driven by A-site cation variation (A = Cs, Rb, K) is a key mechanism for enhancing the switching properties of APbI₃-based flexible memristor devices. This distortion, particularly noticeable in KPbI₃’s orthorhombic phase, alters crystal structure, electronic as well as charge transport properties. Density functional theory (DFT) calculations are performed to calculate ionic migration barriers in the orthorhombic structures, while X-ray photoelectron spectroscopy (XPS) analysis provides insights into the chemical environment and bonding states. Leveraging this effect, KPbI₃ exhibits exceptional non-volatile data storage performance, with a high ON/OFF ratio (∼10³) and self-rectification (∼10³). Conversely, CsPbI₃ with subtle lattice distortion, displays superior synaptic behavior and efficient spike-timing-dependent plasticity (STDP), ideal for neuromorphic computing. CsPbI₃ demonstrates remarkable potential for artificial neural networks (ANNs), achieving ∼97 % accuracy in Modified National Institute of Standards and Technology (MNIST) dataset, image classification with minimal training, and 85 % accuracy in convolutional neural networks (CNNs) on the Canadian Institute for Advanced Research (CIFAR-10) dataset. Our findings highlight the critical role of small cation size in modulating Schottky barriers, morphology, and ionic migration, and their direct impact on resistive switching properties. These results underscore the potential of cation size modulation as an effective strategy for designing memristors for a wide range of applications, including neuromorphic computing, signal processing, logic gates, and quantum computing.