Enhancing multi-state programming and synaptic plasticity through optical stimulation in Bi-alloyed Cs2AgInCl6 double perovskite based memristor

Long-term stability and toxicity issue of the halide perovskite based electronic devices have been aimed to resolve. Considering the requirement of miniaturization without compromising the scaling limit, it is possible to witness, having double halide perovskite as the material of interest. In this work, we have partially substituted the trivalent indium ion with bismuth ion having higher ionic radius in lead-free double perovskite Cs2AgInCl6 by simple solution process. The purpose was novel as it diversified the application of this material in memristor device by initiating optically stimulated response of device conductance. The Au/Cs2AgIn0.8Bi0.2Cl6/ITO device was found to be superior to the Au/Cs2AgInCl6/ITO device in terms of switching window, high-density storage and synaptic plasticity. The improvement in device credibility is attributed to the shift in optical absorption and structural distortion upon bismuth inclusion. Moreover, the film topography of the double perovskite has also enhanced significantly in this process. Bismuth incorporation not only promotes the optical phenomenon in the device but also increases the concentration of bromide vacancies, which is beneficial for the memory and artificial learning performance. Since, the activation energy of bromide ions/vacancies is comparatively low; so, it immensely impacted the device performance due to higher migration rate.