Presence of Metal Chloride for Minimizing the Halide Deficiency and Maximizing the Doping Efficiency in Mn(II)-Doped CsPbCl₃ Nanocrystals

Abstract

Pretreatment using metal chlorides during the formation of halide deficient free perovskite nanocrystals is reported. Among several metal chlorides, Cu­(II)­Cl2 was observed to be ideal for the synthesis of highly emitting CsPbCl3 nanocrystals at high reaction temperature. Because high temperature remained more favorable for the dopant insertion, doping of Mn­(II) was carried out under this halide-rich system, and nearly 68% photoluminescence quantum yield was recorded. Analysis could not provide strong evidence of insertion of Cu­(II) inside the nanocrystals; rather, it was established that Cu­(II)­Cl2 in the system helped to stabilize the reaction even at and above 260 °C and provided an adequate chloride source for obtaining the highly emitting host as well as doped nanocrystals. Details of the physical process involved for this metal ion-induced uplifting of the reaction temperature and the consequent impacts on the nanocrystal formation are studied in detail and reported in this Letter.

Mn2+‐Doped Metal Halide Perovskites: Structure, Photoluminescence, and Application

“…Therefore, CuCl 2 ‐assisted high‐temperature reaction minimize the chloride deficiency in the NCs, and hence, the PLQY is significantly enhanced in the as‐synthesized NCs. [ 216 ] Similarly, Wei et al. also noticed that the introduction of excess Cl − ions into CsPbCl 3 :Mn 2+ NCs can enhance the Mn 2+ PL intensity.…”

“…It is reported that an excessive amount of Cl − ions is able to improve the emission intensity of Mn 2+ ‐doped 3D halide perovskites. [ 142,215–218 ] Lin et al. reported Mn 2+ ‐doped CsPbCl 3 NCs, using SiCl 4 as a promoting reagent in the synthesis process.…”

“…b) Inorganic acid salt addition, including ZnCl 2 , CdCl 2 , SnCl 4 , SbCl 3 , CuCl, and CuCl 2 . [ 216 ] c) HCl acid post treatment. [ 142 ] Mn x ‐NCs stands for the Mn 2+ ‐doped NCs before HCl acid treatment; H‐Mn x ‐NCs stands for the terminal product of HCl acid post‐treated Mn x ‐NCs, where x stands for the content of Mn 2+ precursor.…”

“…[ 215 ] b) PL spectra of Mn 2+ ‐doped CsPbCl 3 with different Cs precursor injection temperatures and normalized at the band‐edge emission position in the presence of CuCl 2 . [ 216 ] c) PL spectra of Mn 2+ ‐doped CsPbCl 3 before and after HCl acid treatment. [ 142 ] d) Normalized PL spectra of Mn 10 ‐NCs treated with PACl and PMACl.…”

Fe2+ doped in CsPbCl3 perovskite nanocrystals: impact on the luminescence and magnetic properties

“…Recently, some researchers reported the transition and alkaline earth metal ion doping into perovskite NCs. [12][13][14][15] For example, Belcher et al demonstrated for the rst time that partially substituting Pb 2+ by Co 2+ at the B-sites of the perovskite lattice was possible. 16 Sun et al had shown that the doping of CsPbX 3 NCs with Ni 2+ ions enabled single-color violet luminescence with near-unity PLQYs.…”