Synthesis of monodisperse PbSe nanorods: a case for oriented attachment.

Monodisperse, high-quality, single-crystal PbSe nanorods were synthesized in a catalyst-free, one-pot reaction using a new phosphine selenide precursor. PbSe nanorods were assembled to provide liquid-crystalline alignment or vertical alignment under controlled evaporation conditions. The growth of nanorods was monitored by TEM and absorption spectroscopy, indicating that oriented attachment could be involved to provide anisotropic PbSe nanostructures. In-plane XRD showed an enhanced (200) peak for PbSe nanorods, indicating the preferred alignment of nanorods on the substrates and their growth along the <100> direction. Absorption and emission spectra, along with lifetime measurements, show the differences between nanoscale PbSe spheres and rods.