Research on the photoluminescence properties of Cu²⁺-doped perovskite CsPbCl₃ quantum dots

CsPbX₃ (X = Cl, Br, and I) quantum dots (QDs) and Cu²⁺-doped CsPbCl₃ QDs with different Cu-to-Pb molar ratios were synthesized via a solvent-based thermal synthesis method. The photoluminescence (PL) properties of these Cu²⁺-doped CsPbCl₃ QDs were also investigated in this study. The results showed that with the increase in the Cl^- concentration the surface defects of CsPb(Cl/Br)₃ QDs increased, which resulted in an increase in the non-radiative recombination of excitons and weakened the PL intensity. Moreover, Cu²⁺-doped CsPbCl₃ QDs maintained the cubic crystal structure of the initial phases. Owing to the doping of Cu²⁺ ions, the surface defects of CsPbCl₃ QDs were effectively eliminated, which facilitated the excitonic recombination via a radiative pathway. The PL quantum yields (PLQYs) of Cu²⁺-doped CsPbCl₃ QDs were increased to 51%, showing great photostability. From the results, it is believed that Cu:CsPbCl₃ QDs can be widely used in optoelectronic devices.