Synthesis of PbSe nanowires: the impact of alkylphosphonic acid addition

Abstract

Reaction of Pb oleate with trioctylphosphine (TOP)/Se in 1-octadecene under appropriate conditions yields PbSe nanowires. The parameters found to be critical for the isolation of exclusively one-dimensional material are the Pb : Se ratio and the temperature profile used during synthesis. Addition of strongly coordinating tetradecylphosphonic acid (TDPA) to the system has a profound impact on the surface morphology, with increasing TDPA concentration producing narrower, smoother nanowires when all other parameters are held constant. The wire morphology and structural data are consistent with a combination of oriented attachment on 〈111〉 surfaces, yielding wires with a [100] axial orientation, and a ligand-mediated competition between growth on 〈111〉, 〈110〉 and 〈100〉 planes. The products possess 10–20 nm diameters, with lengths generally over one micron, and have been characterized through SEM, TEM, EDS, electron diffraction, and optical spectroscopy.