▎ 摘　　要

NOVELTY - Graphene quantum dot-rare earth up-conversion nanocomposite material comprises: histidine-hexamethylene diamine functionalized graphene quantum dots; and ytterbium erbium-doped yttrium sodium fluoride. USE - The nanocomposite material is useful for developing an up-conversion bio sensing nanoplatform for detecting carcinoembryonic antigen (claimed). ADVANTAGE - The nanocomposite material has a high level of sensitivity. DETAILED DESCRIPTION - Graphene quantum dot-rare earth up-conversion nanocomposite material comprises: histidine-hexamethylene diamine functionalized graphene quantum dots; and ytterbium erbium-doped yttrium sodium fluoride. The method for preparing graphene quantum dot-rare earth up-conversion nanocomposite material, comprises: preparation of a histidine-hexamethylene diamine functionalized graphene quantum dot by uniformly mixing citric acid, histidine, and hexamethylene diamine, and fully dissolving the mixture with deionized water, where the molar ratio of the citric acid to the histidine to the hexamethylene diamine is 1:0.6:0.1-1:1.2:0.5, and heating the mixture at a temperature of 150° C; and in-situ hydrothermal synthesis of a substance (in-situ hydrothermal synthesis) by dropwise addition of 20-50 ml of the histidine-hexamethylenediamine functionalized graphene quantum dot water solution into 3-5 ml of a rare earth ion solution under the stirring condition by using the obtained histidine-hexamethylenediamine functionalized graphene quantum dot water sol, where a water solution with a mass concentration of 10-100 mg/ml is prepared first by using histidine-hexamethylenediamine functionalized graphene quantum.