Precise synthetic control over size, shape, and composition of nanocrystals is crucial in bringing these materials to application. Shape control of PbSe nanocrystals, among the most studied nanocrystals for solar devices, has been attained through what appears to be growth by �oriented attachment� of individual PbSe particles. We demonstrate the synthesis of single-crystalline clusters of spherical PbSe nanocrystals wherein individual particles are arranged at the vertices of an octahedron with an apparent void at the center of the particle. The shape and crystallinity of the particles is confirmed by high-res TEM. We show that this entire class of syntheses proceeds through previously unidentified small PbO particles generated in situ prior to injection of the Se precursor. The size and shape of these PbO particles affects the resultant PbSe particle. This discovery deepens our understanding of nanocrystal growth and may lead to a new degree of nanocrystal shape control.

Single crystalline octahedral clusters of spherical PbSe nanocrystals, implications on the mechanism of “oriented attachment” growth of PbSe nanocrystals

243rd National Meeting (2012)

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