Recent advances in crystalline carbon dots for superior application potential

Over the past decade, the field of carbon dots (Cdots) has opened up a completely new area of research in nanoscience and technology because of their extraordinary optical properties and corresponding multifaceted applications. In this review we aim to highlight the green synthesis of Cdots along with recent speculations, demonstrating the origin of their exciting photoluminescence properties. Further, structural engineering, such as surface state modifications, generating crystallinity by heteroatom doping and controlling size, has induced new characteristics in Cdot structures, indispensable for energy conversion and storage applications. This article covers recent findings on generating long-range ordered structures in Cdots and corresponding advancements in energy related applications such as photovoltaic cells, photocatalysis, optoelectronics, batteries and supercapacitors and photothermal energy conversion. Finally, important challenges such as production of crystalline Cdots and future directions of Cdot based research are discussed.