title: Core-shell nanoparticles as building blocks for the bottom-up production of functional nanocomposites: PbTe-PbS thermoelectric properties.
abstract: The bottom-up assembly of nanocrystals provides access to a three-dimensional composition control at the nanoscale not attainable by any other technology. In particular, colloidal nanoheterostructures, with intrinsic multiphase organization, are especially appealing building blocks for the bottom-up production of nanocomposites. In the present work, we use PbTe-PbS as the model material system and thermoelectricity as the paradigmatic application to investigate the potential of the bottom-up assembly of core-shell nanoparticles to produce functional nanocomposites. With this goal in mind, a rapid, high-yield and scalable colloidal synthetic route to prepare grams of PbTe@PbS core-shell nanoparticles with unprecedented narrow size distributions and exceptional composition control is detailed. PbTe@PbS nanoparticles were used as building blocks for the bottom-up production of PbTe-PbS nanocomposites with tuned composition. In such PbTe-PbS nanocomposites, synergistic nanocrystal doping effects result in up to 10-fold higher electrical conductivities than in pure PbTe and PbS nanomaterials. At the same time, the acoustic impedance mismatch between PbTe and PbS phases and a partial phase alloying provide PbTe-PbS nanocomposites with strongly reduced thermal conductivities. As a result, record thermoelectric figures of merit (ZT) of ∼1.1 were obtained from undoped PbTe and PbS phases at 710 K. These high ZT values prove the potential of the proposed processes to produce efficient functional nanomaterials with programmable properties.
authors: Departament d'Electrònica, Universitat de Barcelona, Barcelona 08028, Spain.
authors: Maria
authors: M
authors: Ibáñez
authors: Reza
authors: R
authors: Zamani
authors: Stéphane
authors: S
authors: Gorsse
authors: Jiandong
authors: J
authors: Fan
authors: Silvia
authors: S
authors: Ortega
authors: Doris
authors: D
authors: Cadavid
authors: Joan Ramon
authors: JR
authors: Morante
authors: Jordi
authors: J
authors: Arbiol
authors: Andreu
authors: A
authors: Cabot