Self-powered sensors and wearables: Energy harvesting with nanomaterials for the IoT era

The rise in the application of autonomous sensors and wearable technology is transforming modern life by offering real-time monitoring around the clock, irrespective of the presence of external power sources. Nanomaterials are at the center of driving this transformation by enabling the creation of light, portable, and efficient energy harvesting devices from ambient sources such as mechanical movement, body heat, and sunlight. Triboelectric, piezoelectric, thermoelectric, and photovoltaic nanogenerators are at the forefront of providing scalable alternatives for wearable sensing and IoT applications. These are increasingly being integrated with multifunctional sensors to enable battery-free, seamless sensing in remote, on-body, or hostile environments. The development of nanomaterials including, nanowires, quantum dots, and 2D materials, has enhanced energy conversion efficiency, flexibility, and device integration while also offering desirable properties such as biocompatibility and transparency, which are beneficial for health monitoring and biosensing applications. Long-term reliability, efficient energy storage integration, and mass fabrication remain challenging. To enhance these, multimodal hybrid energy harvesting systems are being produced with the integration of multiple mechanisms to enhance sustained performance and reliability across varying environmental conditions. These technologies are being deployed in smart healthcare, fitness monitoring, environmental sensing, and industrial diagnostics. Interdisciplinary collaboration between materials science, electronics, and analytics is paving the way for innovation and adoption. As growth in the IoT ecosystem continues to grow, the demand for sustainable, self-sustaining technologies will also rise, and nanomaterial-based energy harvesting will prove to be a key enabler for miniaturized, smart, and autonomous sensing platforms that will drive the vision of pervasive computing and wearable intelligence.