Fast reflux synthesis of multi-armed PbS dendrites, influencing factors and optical properties

Abstract

Multi-armed PbS dendrites have been successfully synthesized via a simple reflux route at 120 °C for 10 min, employing ethylene glycol (EG) as the solvent, (CH₃COOH)₂Pb and thiourea as the starting reactants, and cetyltrimethylammonium bromide (CTAB) as the surfactant. The phase and morphology of the as-prepared product was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), (high-resolution) transmission electron microscopy (HR/TEM), selected area electron pattern (SAED) and energy dispersive spectroscopy (EDS). Some factors influencing the formation of multi-armed PbS dendrites were systematically investigated, including the reaction temperature and time, the original S²⁻ion sources, the original amount of CTAB and the sorts of surfactants, the Pb²⁺/S²⁻ molar ratio, and the volume ratio of EG/water. The UV-Vis-near IR spectrum of the product showed that multi-armed PbS dendrites possessed a wide range absorption from ∼230 nm to 1100 nm. Simultaneously, a strong emission peak centered at 343 nm with two shoulder peaks centered at 413 nm and 437 nm, respectively, was presented in the emission spectrum of the product under the excitation of 288 nm light.