Lead‐Free Perovskites for Piezoelectric–Triboelectric Energy Harvesting and Sensing Applications: A Comprehensive Review

Abstract The booming industry of wearable electronics, IoT devices, and self‐powered sensor networks is in critical need of sustainable and efficient mechanical energy harvesting devices. Among the new materials, lead‐free perovskites have garnered significant interest due to their potential to address the environmental and toxicity issues associated with traditional lead‐based systems, while offering good energy conversion and multifunctionality. This review discusses the state‐of‐the‐art of lead‐free perovskite materials in piezoelectric nanogenerators, triboelectric nanogenerators, as well as hybrid devices that use both of these working principles. Specific topics of interest cover material classes and synthesis routes, material properties and characterization, as well as energy harvester developments and their functionalization in various application fields. This review examines the device performance of various perovskite systems and identifies the most effective materials and evaluates their suitability for flexible, stretchable, and wearable applications. Challenges such as stability over long periods of time, scalability in processing, and enhancement of performance are severely discussed with suggestions for future studies. The study highlights lead‐free perovskites as a game‐changer to fabricate green and next‐generation self‐powered energy devices.