Morphology engineering of inorganic nanocrystals with deep eutectic solvents (DESs): Current developments and future prospects

Deep eutectic solvents (DESs) have recently emerged as a promising reaction medium for the synthesis of inorganic nanocrystals with controlled size and morphology. This review article provides a detailed discussion of the fundamental properties of DESs and their versatile roles in synthesizing inorganic nanocrystals. DESs act as dispersing agents, templating agents, capping agents, reducing agents, precursors for metal, etc., to tailor the size and shape of inorganic nanocrystals. Further, the chemical transformation of DESs in the synthesis of nanostructures is elaborated in this review. The interplay between crystal growth kinetics, thermodynamics, and surface chemistry, elucidating how DES influences these factors to achieve control over morphology, is also highlighted through examples of synthesis of various inorganic nanocrystals, including noble metals, metal oxides, chalcogenides, etc. We conclude with a detailed overview of the current significance of DESs in synthesizing morphology-controlled functional nanomaterials, offering a panoramic view of their various roles. Also, the challenges and prospects of using DESs in the morphology-controlled synthesis of nanocrystals are highlighted.