Aqueous synthesis of stable Pb(OH)Br:Cu red phosphor with DFT insights into its luminescence mechanism

Luminescent materials are revolutionizing multiple fields with their unprecedented applications, making them a prominent area of cutting-edge scientific research. Traditionally, the synthesis process involves toxic reagents that are prone to degrade and eventually lead to device instability. Herein, we communicate for the first time the aqueous synthesis of Pb(OH)Br:Cu red phosphor instead of using organic solvents, achieving outstanding stability. The chemical stability of the phosphor remains intact with almost no change in its luminescence intensity, even after being soaked in ethanol and deionized water for ten days. According to first-principles calculations, the doping of Cu⁺ leads to the introduction of defect energy levels and a significant reduction in the bandgap width, enabling electron transitions between the band edges and generating strong red light under ultraviolet excitation. The phosphor operates through a bandgap emission mechanism. Our study provides a green approach for the fabrication of high-performance red phosphors, which significantly reduces the use of organic solvents and the pollution to the environment.