Preparation method of nitrogen-gadolinium doped carbon dot-diatomite nanocomposite latent fingerprint developing powder

A preparation method of nitrogen-gadolinium doped carbon dot-diatomite nano composite material latent fingerprint developing powder belongs to the technical field of fingerprint detection, and comprises the following steps: preparing nitrogen-gadolinium doped carbon dots which are brown under sunlight, and then modifying the carbon dots on the surface with diatomite as a core to obtain the nitrogen-gadolinium doped carbon dot-diatomite nano composite material latent fingerprint developing powder. The yellow nitrogen-gadolinium-doped carbon dot-diatomite nano composite material is prepared by using the nitrogen-gadolinium-doped carbon dots as a raw material, and the nitrogen-gadolinium-doped carbon dots are absorbed and combined through a hierarchical pore structure of diatomite, so that the fluorescence quenching phenomenon caused by carbon dot agglomeration is eliminated, and the fluorescence intensity is obviously enhanced; a light source of 365 nm or 450 nm obliquely irradiates on the displayed fingerprint