Observation of negative surface and interface energies of quantum dots.

Autor:	Calvin JJ; Department of Chemistry, University of California, Berkeley, CA 94720.; Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720., Brewer AS; Department of Chemistry, University of California, Berkeley, CA 94720.; Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720., Crook MF; Department of Chemistry, University of California, Berkeley, CA 94720.; Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720., Kaufman TM; Department of Chemistry, University of California, Berkeley, CA 94720., Alivisatos AP; Department of Chemistry, University of California, Berkeley, CA 94720.; Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720.; Department of Materials Science and Engineering, University of California, Berkeley, CA 94720.; Kavli Energy NanoScience Institute, University of California, Berkeley, CA 94720.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2024 Apr 30; Vol. 121 (18), pp. e2307633121. Date of Electronic Publication: 2024 Apr 22.
DOI:	10.1073/pnas.2307633121
Abstrakt:	Surface energy is a fundamental property of materials and is particularly important in describing nanomaterials where atoms or molecules at the surface constitute a large fraction of the material. Traditionally, surface energy is considered to be a positive quantity, where atoms or molecules at the surface are less thermodynamically stable than their counterparts in the interior of the material because they have fewer bonds or interactions at the surface. Using calorimetric methods, we show that the surface energy is negative in some prototypical colloidal semiconductor nanocrystals, or quantum dots with organic ligand coatings. This implies that the surface atoms are more thermodynamically stable than those on the interior due to the strong bonds between these atoms and surfactant molecules, or ligands, that coat their surface. In addition, we extend this work to core/shell indium phosphide/zinc sulfide nanocrystals and show that the interfacial energy between these materials is highly thermodynamically favorable in spite of their large lattice mismatch. This work challenges many of the assumptions that have guided thinking about colloidal nanomaterial thermodynamics, investigates the fundamental stability of many technologically relevant colloidal nanomaterials, and paves the way for future experimental and theoretical work on nanocrystal thermodynamics. Competing Interests: Competing interests statement:The authors declare no competing interest.
Databáze:	MEDLINE
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