Seed Nucleated Approach as a Key to Controlled Growth of Multi-armed Nanoparticles: The Case of PbS Octapods

Exotic optical, thermoelectric properties and flexibility to exist in different shape and sizes make lead chalcogenides an attractive candidate for many futuristic applications. This report presents a comprehensive study of seed-nucleated controlled growth of multi-armed polyol based lead sulphide (PbS) nanoparticles and propose cubic-to-flower shape-evolution mechanism. While the seed-nucleated strategy was exploited with different concentration of seed-precursors, non-seeded strategy was studied by playing with refluxing time. The seed-nucleated strategy precipitated octapod flowers of smaller particle-size-distribution in 2 h than the non-seeded strategy (in 10 h). The synthesis of highly crystalline nanoparticles, stable to 700 °C, was successfully demonstrated using structural and thermal analysis. The estimated crystallite size for seeded samples were 19–32 nm, whereas for non-seeded they were 35–38 nm. Growth of larger crystallites in non-seeded samples also resulted in larger particle size (120–150 nm) than seeded samples (60–100 nm). Furthermore, the seed-nucleated growth also yield higher available surface area (131.34 m 2 /gm with average-pore-size of 7.49 nm) than non-seeded method. Raman analysis showed that the obtained peaks were in good agreement with transverse optical and longitudinal optical phonon mode of cubic PbS phase. Optimistically, evaluation of this study may helpful to lay roadmap for controlled synthesis of other inorganic crystals.