Iontronics in Hybrid Halide Perovskites for Smart Portable Electronic Devices and Their Challenges

Hybrid halide perovskites have been the materials of the decade as tremendous progress has been observed in perovskite solar cells, perovskite light-emitting diodes, perovskite-based detectors, field effect transistors, and memristor applications. The mixed ionic–electronic conductance characteristic of these materials is one of the most exciting and mysterious processes for the next generation of optoelectronic devices. The primary concern in these perovskite-based optoelectronic devices is an understanding of charge carrier dynamics in the presence of ionic transport. While the theoretical charge carrier mobility in halide perovskites is very high, the experimental values are 2 to 3 orders of magnitude lower than the theoretical value due to strong electron–ion coupling. Also, photoinduced and field-induced ion migrations are the major bottlenecks for the commercialization of perovskite-based optoelectronic devices as they degrade under operating conditions. Therefore, the decoupling of electronic–ionic transport in perovskites may improve the overall charge carrier mobility and device stability. However, ion migration could be beneficial to use in other smart technologies, such as reconfigurable resistive switches for neuromorphic computing, electrolyte-gated electrochemical transistors, photoelectrolysis, and photorechargeable energy storage for next-generation smart portable electronic devices. In this review, we have discussed iontronics in hybrid halide perovskite materials and their applications and challenges in various smart portable electronic devices, including, electrolyte-gated electrochemical transistors, memristors, photorechargeable ion capacitors, photocatalysis, and CO2 reduction.