▎ 摘　　要

NOVELTY - Preparing surface-enhanced Raman scattering (SERS) composite substrate based on colloidal perovskite quantum dot-graphene/nano gold, comprises e.g. (i) taking 0.2 mmol Methylammonium bromide (MABr) and 0.2mmol lead bromide (PbBr2) as precursors using electronic balance and adding into 10 ml dimethylformamide, and completely dissolving to form precursor solution A at 40 KHz, ultrasonically dispersing 40 mu l oleylamine and 800 mu l oleic acid into the precursor solution A to form solution B, ultrasonicating at 40 KHz for 10 minutes, (ii) cutting the silicon (Si) wafer coated with 300 nm thickness silicon dioxide (SiO2) layer into (1-2)x (1-2) cm size, orderly using acetone, ultrasonically cleaning the Si wafer for 20 minutes at a frequency of 20 KHz by ethanol and ultrapure water, (iii) dropping 100 mu l PQD-G colloidal suspension on the rough nano-gold structure using pipette, and allowing to stand for 3 minutes, and (iv) performing Raman detection. USE - The method is useful for preparing surface-enhanced Raman scattering composite substrate based on colloidal perovskite quantum dot-graphene/nano gold. ADVANTAGE - The method is simple, fast and low cost. DETAILED DESCRIPTION - Preparing surface-enhanced Raman scattering (SERS) composite substrate based on colloidal perovskite quantum dot-graphene/nano gold, comprises (i) taking 0.2 mmol Methylammonium bromide (MABr) and 0.2mmol lead bromide (PbBr2) as precursors using electronic balance and adding into 10 ml dimethylformamide, and completely dissolving to form precursor solution A at 40 KHz, ultrasonically dispersing 40 mu l oleylamine and 800 mu l oleic acid into the precursor solution A to form solution B, ultrasonicating at 40 KHz for 10 minutes, and continue to vigorously stirring at 1000 revolutions/minute for 24 hours at room temperature, dropping the solution B in stirring into 10 ml toluene, ultrasonically processing for 20 minutes at 40KHz, forming yellow green colloid solution in the ultrasonic process, indicating successful synthesis of PQD-G, finally centrifuging the formed yellow green colloidal solution at 7000 revolutions/minute for 10 minutes to separate the large nano particles, keeping the upper bright yellow green suspension solution after centrifuging, forming PQD-G with small size, sealing and adding into a sealed drying cabinet, (ii) cutting the silicon (Si) wafer coated with 300 nm thickness silicon dioxide (SiO2) layer into (1-2)x (1-2) cm size, orderly using acetone, ultrasonically cleaning the Si wafer for 20 minutes at a frequency of 20 KHz by ethanol and ultrapure water, and placing the cleaned Si wafer in a vacuum oven to dry at room temperature, dried Si wafer was subjected to the electron beam evaporation (EBE) method in a high vacuum of 4x 10-4 Pa at a voltage of 7 kV and an electron beam current of 60 mA to place the Cr layer in a greenhouse (~25 degrees C) in the Si wafer, depositing a layer of Au powder on the surface of the Si wafer for 70 seconds at a voltage of 7kV and an electron beam current of 70 mA at room temperature (~25 degrees C) for 12 minutes to form a 125 nm nano-gold film, electrochemically roughening the obtained nano-gold film to form a nano-gold structure, the two potential pulses of electrochemical coarsening are: oxidation pulse, oxidation potential is +1.2v, lasting 5 seconds, the cycle time of the potential pulse is set as 8 cycles, washing the electrochemical roughened nano-gold structure by ultra-pure water to remove the adsorbed electrolyte, and drying in the vacuum oven, (iii) dropping 100 mu l PQD-G colloidal suspension on the rough nano-gold structure using pipette, and allowing to stand for 3 minutes, and placing on the nano-Au at a rotation speed of 1000 revolutions/minute in a closed environment, and spin-coating PQD-G colloidal suspension droplets were spin-coated for 60 seconds, and forming the PQD-G/Au composite material, immediately drying in a vacuum drying cabinet, and (iv) performing Raman detection.