Harnessing the Power of 2D Materials for Flexible Energy Harvesting Applications

ABSTRACT Capturing of ambient energy is emerging as a transformative area in energy technology, potentially replacing batteries or significantly extending their lifespan. Harnessing of energy from ambient sources presents a significant opportunity to support sustainable development while mitigating environmental issues. Repurposing energy that would otherwise be wasted from high‐consumption systems such as engines and industrial furnaces is essential for reducing ecological footprints and moving toward carbon‐neutral goals. Furthermore, compact energy harvesting technologies will play a pivotal role in powering the rapidly expanding Internet of Things, enabling innovative advancements in smart homes, cities, industries, and health care that elevate our living standards. To achieve significant advancements in energy harvesting technologies, the development of innovative materials is crucial for converting ambient energy into electricity. In this regard, two‐dimensional (2D) materials, a rising star in the material world, are profoundly and technologically intriguing for energy harvesting. The exceptional atomic thickness, high surface‐to‐volume ratio, flexibility, and tunable band gap effectively enhance their electronic, optical, and chemical properties, making them a potential candidate for use in flexible electronics and wearable energy harvesting technologies. Consequently, these unique properties of 2D materials remarkably enhance their energy harvesting capabilities, including photovoltaic, triboelectric, thermoelectric, and piezoelectric energy harvesting. Here, we present a tutorial‐style review of 2D materials for harvesting energy from different ambient sources (aimed particularly at guiding and educating researchers, especially those new to the field), which starts with a brief overview of the promising properties of 2D materials for energy harvesting, then looks deeply into its advantages as compared to traditional materials along with their 3D counterparts, followed by providing insight into the mechanisms and performance of 2D material–based energy harvesters in portable/wearable electronics, and finally, based on current progress, an overview of the challenges along with corresponding strategies are identified and discussed.