Light-emitting carbon dots extracted from naturally grown torreya grandis seeds

Semiconductor quantum dots (QDs), traditionally based on lead or cadmium, are the promising fluorescent materials for use in bright illumination, detecting and display technology. However, the toxicity of these QDs materials traditionally based on heavy metal cause great concern to human health and environmental protection. Thus, carbon dots from pure natural materials with low toxicity and extensive resources soon raised attention. Here, we introduce a pure physical method to extract carbon dots from the seed's inner skin of torreya grandis which is a Chinese endemic plant widely grown in the southeastern China, such as in Jiangsu, Fujian and Zhejiang Provinces. These carbon dots come from natural plants and only cyclohexane and ethanol with hypotoxicity are used in extracting process to ensure the low toxicity of our material. Besides, we also fabricated light-emitting diodes based on the extracted light-emitting carbon dots. The emission peak of our devices appears at 438 nm with Commission International de I'Eclairage (CIE) color coordinate (0.177, 0.075).