--- res: bibo_abstract: - The potential to control the composition and crystal phase at the nanometer scale enable the production of nanocrystalline materials with enhanced functionalities and new applications. In the present work, we detail a novel colloidal synthesis route to prepare nanoparticles of the ternary semiconductor Cu2GeSe3 (CGSe) with nanometer-scale control over their crystal phases. We also demonstrate the structural effect on the thermoelectric properties of bottom-up-prepared CGSe nanomaterials. By careful adjustment of the nucleation and growth temperatures, pure orthorhombic CGSe nanoparticles with cationic order or polytypic CGSe nanoparticles with disordered cation positions can be produced. In this second type of nanoparticle, a high density of twins can be created to periodically change the atomic plane stacking, forming a hexagonal wurtzite CGSe phase. The high yield of the synthetic routes reported here allows the production of single-phase and multiphase CGSe nanoparticles in the gram scale, which permits characterization of the thermoelectric properties of these materials. Reduced thermal conductivities and a related 2.5-fold increase of the thermoelectric figure of merit for multiphase nanomaterials compared to pure-phase CGSe are systematically obtained. These results are discussed in terms of the density and efficiency of phonon scattering centers in both types of materials.@eng bibo_authorlist: - foaf_Person: foaf_givenName: Maria foaf_name: Ibáñez, Maria foaf_surname: Ibáñez foaf_workInfoHomepage: http://www.librecat.org/personId=43C61214-F248-11E8-B48F-1D18A9856A87 orcid: 0000-0001-5013-2843 - foaf_Person: foaf_givenName: Reza foaf_name: Zamani, Reza foaf_surname: Zamani - foaf_Person: foaf_givenName: Wenhua foaf_name: Li, Wenhua foaf_surname: Li - foaf_Person: foaf_givenName: Doris foaf_name: Cadavid, Doris foaf_surname: Cadavid - foaf_Person: foaf_givenName: Stéphane foaf_name: Gorse, Stéphane foaf_surname: Gorse - foaf_Person: foaf_givenName: Nebll foaf_name: Katchoi, Nebll foaf_surname: Katchoi - foaf_Person: foaf_givenName: Alexey foaf_name: Shavel, Alexey foaf_surname: Shavel - foaf_Person: foaf_givenName: Antonioo foaf_name: López, Antonioo foaf_surname: López - foaf_Person: foaf_givenName: Joan foaf_name: Morante, Joan foaf_surname: Morante - foaf_Person: foaf_givenName: Jordi foaf_name: Arbiol, Jordi foaf_surname: Arbiol - foaf_Person: foaf_givenName: Andreu foaf_name: Cabot, Andreu foaf_surname: Cabot bibo_doi: 10.1021/cm303252q bibo_issue: '23' bibo_volume: 24 dct_date: 2012^xs_gYear dct_language: eng dct_publisher: American Chemical Society@ dct_title: 'Crystallographic control at the nanoscale to enhance functionality: Polytypic Cu2GeSe3 nanoparticles as thermoelectric materials@' ...