▎ 摘　　要

NOVELTY - Making luminescent nanocomposite based on nitrogen and calcium co-doped carbon quantum dots doped bioplastic involves gathering mustard (Brassica) flowers from the nearby agriculture field, cleaning thoroughly in water to obtain a first solution, crushing the stem and leaf pieces into small pieces in a home juicer to get the juice, using Whatman qualitative filter paper (grade 1) to filter the obtained juice to eliminate fibrous contaminants, combining the produced juice with a 10:6 (v/v) ratio of 99.9% pure polyethylene glycol (PEG) solution, performing ultrasonic treatment on the solution mixture for roughly 10 minutes before being put in a 50 ml stainless steel autoclave lined with created Teflon (polytetrafluoroethylene) at room temperature to generate mixture, and performing the solvothermal synthesis by placing the generated mixture 50 cc Teflon-lined stainless-steel autoclave. USE - Method for making luminescent nanocomposite based on nitrogen and calcium co-doped carbon quantum dots doped bioplastic used for down-conversion application in optical display, light-emitting diode and UVC tube. ADVANTAGE - The luminescent nanocomposite based on nitrogen and calcium co-doped carbon quantum dots doped bioplastic is ease to use, cost-effective, eco-friendly, avoided self-quench in solid state owing to aggregation, and is water-soluble, soluble in a wide range of polar and nonpolar solvents, making it possible to produce quantum dot-based displays and in huge quantities. DETAILED DESCRIPTION - Making luminescent nanocomposite based on nitrogen and calcium co-doped carbon quantum dots doped bioplastic involves gathering mustard (Brassica) flowers from the nearby agriculture field, cleaning thoroughly in water to obtain a first solution, crushing the stem and leaf pieces into small pieces in a home juicer to get the juice, using Whatman qualitative filter paper (grade 1) to filter the obtained juice to eliminate fibrous contaminants, combining the produced juice with a 10:6 (v/v) ratio of 99.9% pure polyethylene glycol (PEG) solution, performing ultrasonic treatment on the solution mixture for roughly 10 minutes before being put in a 50 ml stainless steel autoclave lined with created Teflon (polytetrafluoroethylene) at room temperature to generate mixture, performing the solvothermal synthesis by placing the generated mixture 50 cc Teflon-lined stainless-steel autoclave; repeating the solvothermal process at temperature of 150- 220℃ for1-12 hours to produce the light-yellow solution, allowing the solution to cool to ambient temperature, centrifuging for 15 minutes at 10,000 revolutions per minute (rpm), soaking down impurity after centrifugation to obtain a supernatant solution, removing any leftover impurities not removed by centrifugation by filtering the obtained supernatant solution via a 0.22 µm syringe filter (polytetrafluoroethylene membrane), utilizing a lyophilizer (-40℃) to concentrate the produced first solution, storing it for later use, developing the biodegradable bioplastic using commercially vinegar, combining completely glycerine (1:1) with 0.2 gram of corn starch for around 10-15 minutes, following 15 minutes on a hotplate at 50℃, adding dropwise different concentrations of as-synthesized carbon quantum dots (CQDs) solution (5 mg/ml, 10 mg/ml, 20 mg/ml, 80 mg/ml) until thoroughly mixed and stirred for another 10-15 minutes, using a doctored blade method, coating orderly as-prepared CQDs doped bioplastic nanocomposite on a glass slide, using similar casting procedures with CQD solutions of varying pH levels (pH: 2.54, 4.17, 7.4, 10.80), performing alphabet casting, placing the as-prepared CQDs doped bioplastic composite in a plastic cone, compressing slightly to form the letters, curing casting design at room temperature for 24 hours, performing down-convert LEDs, placing the CQDs doped bioplastic nanocomposite mixture in a prefabricated dome-shaped plastic mould that covered a commercial ultraviolet (UVC) light-emitting diode (LED) (275 nanometer (nm), 0.5 watt (W)), allowing to rest at room temperature for 24-48 hours, converting UVC tube, and wrapping the CQDs doped bioplastic nanocomposite film in UVC tube.