<p>Optoionics, involving light-modulated ionic transport in ionic solids, parallels optoelectronics in semiconductors and offers novel device design opportunities across various fields. Among these opportunities, grain boundary phenomena related to radiation-induced electron/hole pair generation and charge trapping at the boundaries causing a modulation in ionic current could enable fast, sensitive, and reversible radiation detectors. The robustness of ionic solids in chemical, structural, and thermal aspects in turn makes them scalable and robust alternatives to traditional semiconductor detectors. This article explores the theoretical underpinnings, experimental breakthroughs, and design considerations needed to optimize such optoionic devices.</p> Graphical abstract <p></p>