Progress in flexible and rigid sensors for highly sensitive detection of heavy metal ions: innovations in material design, fabrication techniques, and real-world applications

Abstract

Heavy metal ion (HMI) contamination threatens the environment’s integrity and human health, indicating the critical need for sensitive and reliable detection methods. The present review critically discusses the most recent flexible and rigid sensor technologies for the detection of HMIs. Flexible sensors are heterogeneous in the following types: adaptability to different shapes, various environments, and real-time monitoring, which make them uniquely appropriate for applications in wearable devices, biomedical applications, and environmental monitoring systems. The non-flexible sensors perform well with great accuracy and sensitivity, especially in laboratory and industrial environments. Recent advances are focused on materials design, fabrication methodologies, and signal processing algorithms, which significantly improve sensor performance and help deploy sensors in complex real-world scenarios. Still, there are drawbacks to the need for more sensitivity, selectivity, durability, and scalability in developing sensors. Future directions for research should involve improvement in the design of materials to use multimodal sensing techniques and develop further miniaturizations and energy efficiency, as well as development of intelligent sensor networks and collaborative work in cross-disciplinary fields. This review can be an essential reference for the scientific and engineering communities focused on developing and applying flexible and non-flexible sensors to detect HMIs.