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

Abstract CsPbBr 3 nanoparticles were synthesized by hot-injection using the pair of reagents MnBr 2 –SbCl 3 and MnBr 2 –SbBr 3 as doping precursors. Said nanoparticles were green-luminescent ( λ 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 MnBr 2 –SbBr 3 as precursors for doping. Transmission electron microscopy and selected area electron diffraction (SAED) revealed a reduced interplanar distance for the (110) planes for such condition ( d 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 CsPbBr 3 nanoparticles synthesized with the MnBr 2– SbCl 3 doping precursor; as a consequence, these nanoparticles displayed a slight blue-shift in their luminescence ( λ em = 508 nm). Meanwhile, undoped CsPbBr 3 nanoparticles decomposed into non-luminescent Cs 4 PbBr 6 with rhombohedral crystal structure before 80 d at ambient condition, as was evidenced by the SAED analysis. Finally, a green-luminescent LED ( λ em = 519 nm) was fabricated using the doped CsPbBr 3 nanoparticles. The achieved stability points to an improvement in the passivation of CsPbBr 3 ’s crystal structure through Sb 3+ and Mn 2+ doping.