Recent advances on cadmium free quantum dots-liquid crystal nanocomposites

Abstract Liquid crystal (LC) nanoscience has been witnessing a paradigm shift towards the dispersion of Cadmium (Cd) based quantum dots (QDs) into LCs to enhance their electro-optical properties and produce highly efficient tunable electro-optical devices. However, the severe toxicity of Cd based QDs impedes their technological impact on the LC based tunable electro-optical devices and hence demands for the usage of Cd-free QDs. Here, we present a critical review on recent accomplishments and insights in the Cd-free QDs doped LC nanocomposites. The investigations on these nanocomposites have clearly demonstrated that the core/shell structure QDs (CIS/ZnS, InP/ZnS and Co-ZnO/ZnO), ZnO and ZnS based QDs, Carbon Dots, and perovskite-quantum dots possess the strong potentials to greatly modulate the properties of LCs and hence could be used as alternative eco-friendly dopants. Moreover, the focus has been made on summarizing how the size and shape dependent optical and electronic properties of Cd-free QDs influence the electrical, electro-optical and photoluminescent properties of different types LCs (i.e. nematic, chiral nematic and ferroelectric). The overview on inclusive existing status, challenges, and future scope of Cd-free QDs-LC nanocomposites has also been discussed. The present review indicates that LC nanocomposites made of Cd-free QDs hold a great promise for their futuristic applications in various robust, low cost, tunable and sustainable electro-optical devices.