Doped-CsPbBr ₃ nanoparticles by the hot-injection method: simultaneous introduction of Mn ²⁺ & Sb ³⁺ ions for increased stability and their application in LEDs

CsPbBr₃nanoparticles were synthesized by hot-injection using the pair of reagents MnBr₂-SbCl₃and MnBr₂-SbBr₃as doping precursors. Said nanoparticles were green-luminescent (<i>λ</i>_em= 515 nm) with an average particle size of ∼12 nm and with monoclinic and orthorhombic crystal structure lasting longer than 80 d at ambient conditions. Additionally, a 54% photoluminescence quantum yield was maintained for at least 60 d when using MnBr₂-SbBr₃as precursors for doping. Transmission electron microscopy and selected area electron diffraction (SAED) revealed a reduced interplanar distance for the (110) planes for such condition (<i>d</i>_hkl= 0.57 nm-0.56 nm), suggesting heterogeneous doping into the analyzed nanoparticles, along with chemical analysis. On the other hand, Cl was detected through energy dispersive x-ray spectroscopy in the CsPbBr₃nanoparticles synthesized with the MnBr_2-SbCl₃doping precursor; as a consequence, these nanoparticles displayed a slight blue-shift in their luminescence (<i>λ</i>_em= 508 nm). Meanwhile, undoped CsPbBr₃nanoparticles decomposed into non-luminescent Cs₄PbBr₆with rhombohedral crystal structure before 80 d at ambient condition, as was evidenced by the SAED analysis. Finally, a green-luminescent LED (<i>λ</i>_em= 519 nm) was fabricated using the doped CsPbBr₃nanoparticles. The achieved stability points to an improvement in the passivation of CsPbBr₃'s crystal structure through Sb³⁺and Mn²⁺doping.