Synthesis and Shape Evolution of Star-shaped PbSe Nanocrystals
Star-shaped PbSe nanocrystals capped with oleic acid were synthesized in solution from lead oleate and trioctylphosphine selenide precursors when lead acetate trihydrate served as the lead source. The prepared nanocrystals were characterized by X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectrometer. The nanocrystals have the same cubic rock salt lattice structure as the bulk PbSe. The initial injection of trioctylphosphine selenide into hot lead oleate solution immediately results in the formation of truncated octahedron-shaped nuclei, which are terminated by 100 faces and 111 faces. The growth along <100> direction is faster than that along <111> direction, which induces the shrinking of the six 100 faces into sharp corners and finally gives rise to star-shaped nanocrystals. It is conformed that acetate in the reaction mixture plays an important role in controlling the growth mechanism and the resulting shape of nanocrystals. In addition, the reaction solvent also influences the shape of nanocrystals. The Fourier transform infrared absorption spectrum of PbSe nanocrystals dissolved in tetrachloroethylene shows two peaks at 1500nm and 2100nm, indicating the band gap of prepared nanocrystal is 0.59eV. Due to the effects of quantum confinement, the absorption peaks exhibit dramatic blue shift from the band gap of bulk PbSe.
PbSe Nanocrystals Shape Solution Route
袁林 张道礼 张建兵 胡云香
华中科技大学,电子科学与技术系,武汉430074
国际会议
成都
英文
2007-11-19（万方平台首次上网日期，不代表论文的发表时间）