Impeding anion exchange to improve composition stability of CsPbX3（X= Cl, Br） nanocrystals through facilely fabricated Cs4Pb6 shell

Inorganic lead halide perovskite nanocrystals(NCs)with superior photoelectric properties are expected to have excellent performance in many fields.However,the anion exchange changes their features and is unfavorable for their applications in many fields.Hence,impeding anion exchange is important for improving the composition stability of inorganic lead halide perovskite NCs.Herein,CsPb X3(X=Cl,Br)NCs are coated with Cs4PbX6 shell to impede anion exchange and reduce anion mobility.The Cs4PbX6 shell is facily fabricated on CsPbX3 NCs through high temperature injection method.Anion exchange experiments demonstrate that the Cs4 PbX6 shell completely encapsulates CsPbX3 NCs and greatly improves the composition stability of CsPbX3 NCs.Moreover,our work also sheds light on the potential design approaches of various heterostructures to expand the application of CsPbM3(M=Cl,Br,I)NCs.

Water triggered interfacial synthesis of highly luminescent CsPbX3:Mn2+ quantum dots from nonluminescent quantum dots

Currently,lead halide perovskite quantum dots(PeQDs)have attracted great attention due to their spectacular photophysical properties.However,the toxicity of Pb2+heavy metal ions in CsPbX3 PeQDs limits their practical applications.Herein,a facile post-treatment doping method is proposed,which enables the preparation of highly luminescent low-toxic CsPbX3:Mn^2+PeQDs from nonluminescent Cs4PbX6 PeQDs at water interface.The monodispersed CsPbX3:Mn^2+PeQDs exhibit excellent photophysical properties,including high photoluminescence quantum yield up to 87%.The reaction process and doping mechanism are deeply explored through in-situ monitoring.By simply adjusting the halide composition of the original Cs4PbX6 PeQDs or Mn doping concentration,a series of CsPbX3:Mn^2+PeQDs with adjustable emission could be obtained.Further,the CsPbX3:Mn^2+Q-LED was fabricated and exhibited excellent orange light with the color coordinates of(0.564,0.399),correlated color temperature(CCT)of 1,918 K,and luminous efficiency(LE)of 24 lm/W,which illustrate the great promise in light emitting diode(LED)applications.This work not only provides a facile method for the preparation of highly luminescent low-toxic CsPbX3:Mn^2+PeQDs,but also provides insights into the mechanism of doping process.