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.

液晶（LC）纳米科学已经看到向基于Cd（Cd）的量子点（QD）分散到LC中以增强其电光特性并生产高效可调谐电光器件的范例转变。然而，基于镉的量子点的严重毒性阻碍了它们对基于LC的可调谐电光器件的技术影响，因此要求使用无镉的量子点。在这里，我们对无镉量子点掺杂的LC纳米复合材料的最新成就和见解进行了重要的评论。对这些纳米复合材料的研究清楚地表明，核/壳结构量子点（CIS / ZnS，InP / ZnS和Co-ZnO / ZnO），基于ZnO和ZnS的量子点，碳点，钙钛矿和量子点具有强大的潜力，可以极大地调节LC的性能，因此可以用作替代的环保型掺杂剂。此外，重点放在总结无镉量子点的尺寸和形状相关的光学和电子特性如何影响不同类型LC（即向列，手性向列和铁电）的电，电光和光致发光特性。还讨论了无镉QDs-LC纳米复合材料的包容性现状，挑战和未来范围的概述。本综述表明，由无镉量子点制成的LC纳米复合材料在各种坚固，低成本，可调谐和可持续的电光设备中的未来应用前景广阔。重点是概述无镉量子点的尺寸和形状相关的光学和电子特性如何影响不同类型LC（即向列，手性向列和铁电）的电，电光学和光致发光特性。还讨论了无镉QDs-LC纳米复合材料的包容性现状，挑战和未来范围的概述。本综述表明，由无镉量子点制成的LC纳米复合材料在各种坚固，低成本，可调谐和可持续的电光设备中的未来应用前景广阔。重点是概述无镉量子点的尺寸和形状相关的光学和电子特性如何影响不同类型LC（即向列，手性向列和铁电）的电，电光学和光致发光特性。还讨论了无镉QDs-LC纳米复合材料的包容性现状，挑战和未来范围的概述。本综述表明，由无镉量子点制成的LC纳米复合材料在各种坚固，低成本，可调谐和可持续的电光设备中的未来应用前景广阔。挑战，以及无镉QDs-LC纳米复合材料的未来范围也进行了讨论。本综述表明，由无镉量子点制成的LC纳米复合材料在各种坚固，低成本，可调谐和可持续的电光设备中的未来应用前景广阔。挑战，以及无镉QDs-LC纳米复合材料的未来范围也进行了讨论。本综述表明，由无镉量子点制成的LC纳米复合材料在各种坚固，低成本，可调谐和可持续的电光设备中的未来应用前景广阔。