▎ 摘　　要

NOVELTY - Preparation of Pyrostegia venusta derived fluorescent carbon quantum dots (CQDs)and composite, and their use for latent fingerprint and anti-counterfeit applications, involves: 1) collecting Pyrostegia venusta flower petals and rinsing in deionized water; 2) chopping flowers and boiling to obtain juice; 3) filtering formed juice, to remove fibrous impurities; 4) sonicating mixture; 5) subjecting mixture to microwave; 6) microwave treating until brown viscous fluid is formed; 7) cooling formed solution, centrifuging to form supernatant solution; 8) removing any remaining impurities not removed by centrifugation, by filtering the supernatant solution; 9) adding 5g commercial corn flour and a drop casting CQDs solution (3-4 ml), with a 20 μl pipette while vigorously stirring; and t. embedding the CQDs in the corn flour matrix after grinding into a fine powder. USE - Method is used for preparing Pyrostegia venusta derived fluorescent carbon quantum dots and their composite used in forensic analysis and anti-counterfeiting ink. ADVANTAGE - The prepared fluorescent carbon quantum dots enable efficient, rapid, portable and user-friendly fingerprint detection. A proof-of-concept anti-counterfeiting tag, based on prepared carbon quantum dots CQDs ink, is also exhibited by the use of biocompatible and non-toxic fluorescent CQDs obtained from the begonia flower Pyrostegia venusta. DETAILED DESCRIPTION - Facile one-step microwave-assisted green synthesis of Pyrostegia venusta derived fluorescent carbon quantum dots (CQDs)and composite, as well as their use for latent fingerprint and anti-counterfeit applications, involves: 1) collecting Pyrostegia venusta flower petals and thoroughly rinsing in deionized water; 2) chopping the flowers into pieces and boiling to obtain juice; 3) using Whatman qualitative filter paper (grade 1) to filter formed juice, to remove fibrous impurities; 4) sonicating the mixture obtained in step 3, for 15 minutes, at room temperature; 5) subjecting the mixture to microwave, at power 127.5-750 watts (W); 6) processing in microwave until a brown viscous fluid is obtained, based on the fluorescence intensity, using 360W (medium low) microwave synthesis solution; 7) cooling the formed solution to room temperature, centrifuging for 15 minutes, at speed 7000-8000 rotations/minute (rpm), to form the supernatant solution; 8) removing any remaining impurities not removed by centrifugation, by filtering the supernatant solution, through a 0.22 micrometer syringe filter (polytetrafluoroethylene membrane); 9) adding 5g commercial corn flour and a drop casting CQDs solution (3-4 ml), with a 20 μl pipette while vigorously stirring; and t. embedding the CQDs in the corn flour matrix after grinding into a fine powder.