Effect of morphology and concentration on capping ability of surfactant in shape controlled synthesis of PbS nano- and micro-crystals

Micro- and nano-crystals of PbS with different morphologies have been successfully prepared at 80 °C under aqueous phase conditions by using cationic Gemini/dimeric (m-s-m) surfactants as capping agents. The effect of Gemini spacer length and concentration has been evaluated to make PbS crystal synthesis more selective. Well-defined PbS nano- and micro-structures including dendrites, nanocubes, and truncated nanocubes were selectively synthesized by varying the spacer length of Gemini surfactants. The shape and size controlled synthesis of PbS crystals was obtained due to preferential adsorption of Gemini surfactants. To provide a comparison between monomeric and dimeric surfactants, PbS crystals have also been synthesized using DTAB (a conventional monomeric counterpart of Gemini surfactant) as a capping agent.