Luminescent manganese-doped CsPbCl₃ perovskite quantum dots

Nanocrystalline cesium lead halide perovskites (CsPbX₃, X = Cl, Br, and I) form an exciting new class of semiconductor materials showing quantum confinement. The emission color can be tuned over the full visible spectral region making them promising for light‒emitting applications. Further control over the optical and magnetic properties of quantum dots (QDs) can be achieved through doping of transition metal (TM) ions such as Mn²⁺ or Co²⁺. Here we demonstrate how, following QD synthesis in the presence of a Mn‒precursor, dropwise addition of silicon tetrachloride (SiCl₄) to the QDs in toluene results in the formation of Mn‒doped CsPbCl₃ QDs showing bright orange Mn²⁺ emission around 600 nm. Evidence for successful doping is provided by excitation spectra of the Mn²⁺ emission, with all features of the CsPbCl₃ QD absorption spectrum and a decrease of the 410 nm excitonic emission life time with increasing Mn‒concentration, giving evidence for enhanced exciton to Mn²⁺ energy transfer. As a doping mechanism we propose a combination of surface etching and reconstruction and diffusion doping. The presently reported approach provides a promising avenue for doping TM ions into perovskites QDs enabling a wider control over optical and magnetic properties for this new class of QDs.