A Novel Synthesis Method of Dumbbell-like (Gd 1- x Tb x ) 2 O(CO 3 ) 2 ·H 2 O Phosphor for Latent Fingerprint

A novel method for synthesizing dumbbell-shaped (Gd Tb ) O(CO ) ·H O (GOC: Tb ) phosphors using sodium carbonate was investigated. An amount of 1 mmol of stable fluorescent powder can be widely prepared using 3-11 mmol of Na CO at a pH value of 8.5-10.5 in the reaction solution. The optimal reaction conditions for the phosphors were determined to be 7 mmol for the amount of sodium carbonate and a pH of 9.5 in the solution. Mapping analysis of the elements confirmed uniform distribution of Gd and Tb elements in GOC: Tb . The analysis of fluorescence intensity shows that an optimal excitation wavelength of 273 nm is observed when the concentration of Tb is between 0.005 and 0.3. The highest emission intensity was observed for GOC:0.05Tb with a 57.5% maximum quantum efficiency. The chromaticity coordinates show that the color of GOC:Tb is stable and suitable for fluorescence recognition. Latent fingerprint visualization reveals distinctive features like whorls, hooks, and bifurcations. Therefore, the sodium carbonate method offers an effective alternative to traditional urea chemical reaction conditions for preparing GOC:Tb .