Influence of the capping agents on synthesis of Bi2Te3 nanotubes by solution-phase reaction.

Bi2Te3 nanotubes were synthesized by first synthesizing Te nanorods and then alloying it with Bi(O) reduced from Bi3+ using solution-phase reaction. The alloying of Bi(0) and Te nanorods was enabled by the atomic diffusion on the interface between two metals. The morphology of Bi2Te3 crystals was greatly influenced depending on kind and concentration ratio of capping agents during solution-phase reaction. When only a trioctylphosphine oxide (TOPO) was used as a capping agent, the cylinder like Bi2Te3 nanotubes with diameters of 130-160 nm or larger were formed while the rod like Bi2Te3 nanobelts with diameters of 25-40 nm were formed when only poly vinyl pyrrolidone (PVP) was used. When the mixture of trioctylphosphine oxide and poly vinyl pyrrolidone was used, Bi2Te3 nanotubes with diameters of 30-80 nm were formed.