Doped-Cspbbr3 Nanoparticles by the Hot-Injection Method: Simultaneous Introduction of Mn2+ & Sb3+ Ions for Increased Stability and Their Application in Leds

Abstract

CsPbBr3 nanoparticles were synthetized by hot-injection using the pair of reagents MnBr2 – SbCl3 and MnBr2 – SbBr3 as doping precursors. Said nanoparticles were green-luminescent (λem = 515 nm) with an average particle size of ~12 nm and with monoclinic and orthorhombic crystal structure lasting longer than 80 days at ambient conditions. Additionally, a 54% photoluminescence quantum yield (PLQY) was maintained for at least 60 days when using MnBr2 – SbBr3 as precursors for doping. Transmission electron microscopy (HRTEM) and electron diffraction (SAED) revealed a reduced interplanar distance for the (110) planes for such condition (dhkl = 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 (EDXS) in the CsPbBr3 nanoparticles synthetized with the MnBr2 – SbCl3 doping precursor; as a consequence, these nanoparticles displayed a slight blue-shift in their luminescence (λem = 508 nm). Meanwhile, undoped CsPbBr3 nanoparticles decomposed into non-luminescent Cs4PbBr6 with rhombohedral crystal structure before 80 days at ambient condition, as was evidenced by the SAED analysis. Finally, a green-luminescent LED (λem = 519 nm) was fabricated using the doped CsPbBr3 nanoparticles. The achieved stability points to an improvement in the passivation of CsPbBr3’s crystal structure through Sb3+ and Mn2+ doping.

Keywords: CsPbBr3 nanoparticles, Doped nanoparticles, optoelectronic properties, ambient stability