  Metal halide perovskite-based materials have emerged over the past few
decades as remarkable solution-processable opto-electronic materials with many
intriguing properties and potential applications. These emerging materials have
recently been considered for their promise in low-energy memory and information
processing applications. In particular, their large optical cross-sections,
high photoconductance contrast, large carrier diffusion lengths, and mixed
electronic/ionic transport mechanisms are attractive for enabling memory
elements and neuromorphic devices that are written and/or read in the optical
domain. Here, we review recent progress toward memory and neuromorphic
functionality in metal halide perovskite materials and devices where photons
are used as a critical degree of freedom for switching, memory, and
neuromorphic functionality.
