Bifunctional photoactive nanomaterials for sustainable paper-based photobatteries: powering point-of-care medical biosensors

Abstract

Most of the point-of-care (POC) POC diagnostics systems require a fluid manipulation that can be controlled by microfluidic components, such as micropumps, microvalves, and micro-separators, among others. These microfluidic components require significant external energy to apply external forces. Hence, the lack of reliable and sustainable power sources impedes the widespread adoption of these devices. Since the 1970s, photobatteries have been the subject of scientific inquiry with a resurgence in recent years, catalysing the creation of diverse photobattery designs. Among these, paper-based systems have emerged as a particularly promising avenue, offering a potential solution to mitigate the environmental footprint of disposable energy storage devices. Their performance and longevity, however, are heavily dependent on the photoactive battery electrode materials and architectures employed. This comprehensive review article examines the cutting-edge research on bifunctional nanomaterials optimally suited for paper-based lithium-ion photobatteries. The focus is primarily on two-electrode configurations where a single electrode integrates both light harvesting and energy storage capabilities. Such a design is particularly advantageous for electrochemical point-of-care (POC) medical sensors, offering a compact and efficient energy solution. The work highlights the unique requirements and challenges associated with these systems and provides a comprehensive overview of potential photoactive materials. It critically evaluates their performance metrics, such as specific energy, power density, safety, and environmental impact, in the context of solar-powered POC medical sensor applications. Successful case studies and real-world applications are discussed, showcasing their potential to improve healthcare accessibility and quality, particularly in underserved and resource-constrained communities. This review underscores the transformative potential of nanostructure photobatteries and beckons researchers to partake in shaping this new field.