Synergetic effects of the co-doping transition metal ions and the silica-shell coating for enhancing the photoluminescence and stability of Mn: CsPbCl3 nanocrystals and their application

Doping Mn 2+ ions into cesium lead halide CsPbX 3 (X = Cl, Br, I) perovskite nanocrystals (PNCs) has been proven to be an effective strategy to reduce the Pb 2+ content. However, excessive Mn 2+ ions may form the Mn–Mn dimers in PNCs, leading to concentration quenching effects and low photoluminescence quantum yields (PLQYs). Herein, secondary metal ions (Ni 2+ , Cu 2+ , Zn 2+ ) were introduced to substitute Pb 2+ ions as co-doped (Mn, M):CsPbCl 3 PNCs (M = Ni, Cu, Zn), which were prepared by a facile method under ambient conditions, aiming for positively passivating the surface defects and improving the Mn 2+ emission. Also, to protect the co-doped (Mn, M):CsPbCl 3 PNCs from moisture damage, we performed silica encapsulation, which further passivated surface defects due to the effective hydrolysis of silane . The evolution of optical properties and stabilities of three series of (Mn, M):CsPbCl 3 PNCs was compared. The PLQYs of co-doped (Mn, M):CsPbCl 3 PNCs were larger than those of single-doped Mn: CsPbCl 3 PNCs, especially for (Mn, Ni):CsPbCl 3 and (Mn, Cu):CsPbCl 3 , which can reach nearly 30%. The PLQYs of (Mn, Ni):CsPbCl 3 and (Mn, Zn):CsPbCl 3 PNCs decreased dramatically during the encapsulation process, while the PLQY values of (Mn, Cu):CsPbCl 3 remained 30% even after the same treatment process. Consequently, the prototypes of white light-emitting devices (WLEDs) were successfully fabricated based on orange-red (Mn, Ni):CsPbCl 3 @SiO 2 and (Mn, Zn):CsPbCl 3 @SiO 2 composites. The synergetic effects of co-doping transition metal ions and silica-shell coating on improving optical properties and stabilities were investigated. It has potential for a wide range of applications in the field of solid-state light emission.