title: PbTe colloidal nanocrystals: synthesis, characterization, and multiple exciton generation.
abstract: We report an alternative synthesis and the first optical characterization of colloidal PbTe nanocrystals (NCs). We have synthesized spherical PbTe NCs having a size distribution as low as 7%, ranging in diameter from 2.6 to 8.3 nm, with first exciton transitions tuned from 1009 to 2054 nm. The syntheses of colloidal cubic-like PbSe and PbTe NCs using a PbO "one-pot" approach are also reported. The photoluminescence quantum yield of PbTe spherical NCs was measured to be as high as 52 +/- 2%. We also report the first known observation of efficient multiple exciton generation (MEG) from single photons absorbed in PbTe NCs. Finally, we report calculated longitudinal and transverse Bohr radii for PbS, PbSe, and PbTe NCs to account for electronic band anisotropy. This is followed by a comparison of the differences in the electronic band structure and optical properties of these lead salts.
authors.affiliation: Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado 80401, USA. james_murphy@nrel.gov
authors.forename: James E
authors.initials: JE
authors.lastname: Murphy
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Beard
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Norman
authors.forename: S Phillip
authors.initials: SP
authors.lastname: Ahrenkiel
authors.forename: Justin C
authors.initials: JC
authors.lastname: Johnson
authors.forename: Pingrong
authors.initials: P
authors.lastname: Yu
authors.forename: Olga I
authors.initials: OI
authors.lastname: Mićić
authors.forename: Randy J
authors.initials: RJ
authors.lastname: Ellingson
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Nozik