Preparation of barium ion-doped carbon quantum dots, prepared carbon quantum dots and application of prepared carbon quantum dots

The invention discloses preparation of barium ion-doped carbon quantum dots, the prepared carbon quantum dots and application of the prepared carbon quantum dots. The preparation of the barium ion-doped carbon quantum dots comprises the steps of: dispersing a carbon source, a nitrogen source and a barium source in an organic solvent, and carrying out a solvothermal reaction to obtain the barium ion-doped carbon quantum dots. The simple preparation method is only a simple mix heating reaction without introduction of complex functional groups which are needed for an organic reaction, and is suitable for industrial application; furthermore, the obtained barium ion-doped carbon quantum dots have very high fluorescence quantum yield of up to 96.7%, meanwhile, the barium ion-doped carbon quantumdots have good fluorescence performance in organic solvents, but the fluorescence intensity is significantly quenched after a small amount of water is added, so that the barium ion-doped carbon quantum dots are applied to detection of water content in the organic solvents, and a detection limit of 0.01% is achieved.