Organometallic-Route Synthesis, Controllable Growth, Mechanism Investigation, and Surface Feature of PbSe Nanostructures with Tunable Shapes

Lead selenide (PbSe) nanostructures with well-defined star-shaped morphology are successfully fabricated via a facile organometallic synthetic route from the reaction of tetraphenyl lead (Ph4Pb) with triphenylphosphine selenide (Ph3PSe) in dibenzylamine (DBA) with the assistance of oleic acid (OA) and oleylamine (OAm) at 220 degrees C for 30 min. The structure and shape of the nanocrystals are investigated by techniques of XRD, SEM, TEM, HRTEM, SAED, and EDX, and it is interesting that the obtained PbSe nanostars present Pb-rich features, although the PbSe nanostars are still in typical rock salt phase. Experimental investigations and ATR-FTIR studies demonstrate that the media of DBA, OA, and OAm with an order OA > DAB > OAm play important roles in the growth of the PbSe nanostars with well-defined shapes because the media not only serve as solvents but capping materials. The synergetic effects of the media are also favorable for the growth of PbSe nanocrystals with the well-defined star-shaped morphologies in the current reaction system. Meanwhile, varied PbSe nanostructures with cubic, side-cut cubic, and octahedral shapes can be fabricated by regulating the relevant reaction conditions, and all of these nanostructures prepared in the procedures demonstrate Pb-rich features due to the selective capping effects of the media to the exposed Pb(II) ions. It is confirmed that the specific shape and geometry of the nanostructures can be tuned by controlling the exposed crystal surfaces and/or the corresponding compositions via the variation of reaction conditions in the media.