caa a22 4500 530097613 20181125125408.0 cr unu---uuuuu 181026s2018 xx s 000 0 eng 10.3929/ethz-b-000292760 doi 10.28954/2018.csq.02.001 doi (ETHRESEARCH)oai:www.research-collection.ethz.ch:20.500.11850/292760 Ligand-induced symmetry breaking, size and morphology in colloidal lead sulfide QDs: from classic to thiourea precursors [Elektronische Daten] [Federica Bertolotti, Andrew H. Proppe, Dmitry; id_orcid 0000-0002-5187-4555 Dirin, Mengxia Liu, Oleksandr Voznyy, Antonio Cervellino, Simon J.L. Billinge, Maksym V. Kovalenko, Edward H. Sargent, Norberto Masciocchi, Antonietta Guagliardi] Chem. Sq. Open access ethresearch Colloidal lead chalcogenide quantum dots (CQDs) exhibit promising optoelectronic properties for applications in solar cell devices and as thermoelectrics. Herein, we report and discuss a ferroelectric structural distortion, at the picometer scale resolution, in PbS CQDs prepared using both classic and new synthetic pathways. The investigation was performed using synchrotron X-ray total scattering data and advanced methods of analysis that rely on a homo-core-shell model and evaluate the atomic arrangement, stoichiometry, size and morphology of nanocrystals. The CQDs show comparable size-dependent relative elongation, up to 0.7 % of one body diagonal of the cubic rock-salt structure, which corresponds to a rhombohedral lattice deformation. The findings suggest a joint role for the oleate ligands (which induce surface tensile strain) and the Pb(II) lone pair as the driving forces of the deformation. Pb displacements along the [111] direction, which provoke a ferrolectric distortion related to the lattice change, fall in the 0.0 - 0.1 Å. Overall, the findings suggest the local nature of the metal off-centering, leading to different average displacements which depend on the synthetic conditions. Creative Commons Attribution 4.0 International http://creativecommons.org/licenses/by/4.0 ethresearch Lead Chalcogenides ethresearch Quantum Dots ethresearch Nanocrystallography ethresearch X-ray Total Scattering ethresearch Debye Scattering Equation ethresearch Pair Distribution Function ethresearch Nanocrystal Morphology ethresearch Bertolotti Federica joint author Proppe Andrew H. joint author Dirin Dmitry; id_orcid 0000-0002-5187-4555 joint author Liu Mengxia joint author Voznyy Oleksandr joint author Cervellino Antonio joint author Billinge Simon J.L. joint author Kovalenko Maksym V. joint author Sargent Edward H. joint author Masciocchi Norberto joint author Guagliardi Antonietta joint author Chemistry Squared Barcelona : Association Science^2 2, p. 1 2604-0794 http://hdl.handle.net/20.500.11850/292760 text/html WWW-Backlink auf das Repository (Open access) 1 Journal Article ethresearch ETHRESEARCH 856 40 http://hdl.handle.net/20.500.11850/292760 text/html WWW-Backlink auf das Repository (Open access) ETHRESEARCH 700 1- Bertolotti Federica joint author ETHRESEARCH 700 1- Proppe Andrew H. joint author ETHRESEARCH 700 1- Dirin Dmitry; id_orcid 0000-0002-5187-4555 joint author ETHRESEARCH 700 1- Liu Mengxia joint author ETHRESEARCH 700 1- Voznyy Oleksandr joint author ETHRESEARCH 700 1- Cervellino Antonio joint author ETHRESEARCH 700 1- Billinge Simon J.L. joint author ETHRESEARCH 700 1- Kovalenko Maksym V. joint author ETHRESEARCH 700 1- Sargent Edward H. joint author ETHRESEARCH 700 1- Masciocchi Norberto joint author ETHRESEARCH 700 1- Guagliardi Antonietta joint author ETHRESEARCH 773 0- Chemistry Squared Barcelona : Association Science^2 2, p. 1 2604-0794 BK010053 XK010053 XK010000 ETHRESEARCH ETHRESEARCH ETHRESEARCH Journal Article Open access