Enhanced formation of PbSe nanorods via combined solution-liquid-solid growth and oriented attachment

With the aid of Bi catalysts dispersed in a precursor solution, PbSe nanorods were successfully synthesized by solution-liquid-solid (SLS) growth of PbSe nanocrystals followed by oriented attachment of adjacent PbSe nanoparticles. The processing temperature and time for the nanorod synthesis were markedly reduced to 180 °C and 1 min, respectively. The as-synthesized PbSe nanorods were in necklace shapes with ∼10 to 20 nm in diameter and ∼400 to 700 nm in length. The nanorods were highly crystalline, showing 〈100〉 preferential growth orientation. The exactly identical experimental conditions excluding Bi catalysts produced only spherical shape PbSe nanoparticles with ∼10 nm in diameter. The primary PbSe nanocrystals produced by Bi catalysts via SLS growth could have net dipole moments due to the elongation into 〈100〉 orientation and they can attract nearby Bi catalyst-free PbSe nanoparticles successively to grow into one-dimensional nanorods.