"Darker-than-Black" PbS Quantum Dots: Enhancing Optical Absorption of Colloidal Semiconductor Nanocrystals via Short Conjugated Ligands.
Colloidal quantum dots (QDs) stand among the most attractive light-harvesting materials to be exploited for solution-processed optoelectronic applications. To this aim, quantitative replacement of the bulky electrically insulating ligands at the QD surface coming from the synthetic procedure is mand...
| Publicado en: | Journal of the American Chemical Society Vol. 137; no. 5; pp. 1875 - 1887 |
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| Autores principales: | , , , , , |
| Formato: | Artículo |
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American Chemical Society
2/11/2015
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=101328794&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 101328794 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 2/11/2015 vid: 137 iid: 5 pid: 997 pub: American Chemical Society artinfo: ui: 101328794 10.1021/ja510739q ppf: 1875 ppct: 12 formats: tig: atl: "Darker-than-Black" PbS Quantum Dots: Enhancing Optical Absorption of Colloidal Semiconductor Nanocrystals via Short Conjugated Ligands. aug: au: Giansante, Carlo Infante, Ivan Fabiano, Eduardo Grisorio, Roberto Suranna, Gian Paolo Gigli, Giuseppe affil: Center for Biomolecular Nanotechnologies @UNILE, Istituto Italiano di Tecnologia, via Barsanti 1, 73010 Arnesano, Lecce, Italy NNL-CNR Istituto di Nanoscienze, via per Arnesano, 73100 Lecce, Lecce, Italy Kimika Fakultatea, Euskal Herriko Unibersitatea and Donostia International Physics Center (DIPC), CP1072, 20080 San Sebastian, Spain Department of Theoretical Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, Netherlands DICATECh - Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica, Politecnico di Bari, via Orabona 4, 70125 Bari, Italy Dipartimento di Matematica e Fisica 'E. De Giorgi', Università del Salento, via per Arnesano, 73100 Lecce, Lecce, Italy Istituto di Metodologie Inorganiche e dei Plasmi (I.M.I.P), Via Amendola 122/D, 70126 Bari, Italy su: Semiconductor nanocrystals Optoelectronic devices Conjugated polymers Density functional theory Thiol synthesis Ligands (Chemistry) sug: subj: Semiconductor nanocrystals Optoelectronic devices Conjugated polymers Density functional theory Thiol synthesis Ligands (Chemistry) ab: Colloidal quantum dots (QDs) stand among the most attractive light-harvesting materials to be exploited for solution-processed optoelectronic applications. To this aim, quantitative replacement of the bulky electrically insulating ligands at the QD surface coming from the synthetic procedure is mandatory. Here we present a conceptually novel approach to design light-harvesting nanomaterials demonstrating that QD surface modification with suitable short conjugated organic molecules permits us to drastically enhance light absorption of QDs, while preserving good long-term colloidal stability. Indeed, rational design of the pendant and anchoring moieties, which constitute the replacing ligand framework leads to a broadband increase of the optical absorbance larger than 300% for colloidal PbS QDs also at high energies (>3.1 eV), which could not be predicted by using formalisms derived from effective medium theory. We attribute such a drastic absorbance increase to ground-state ligand/QD orbital mixing, as inferred by density functional theory calculations; in addition, our findings suggest that the optical band gap reduction commonly observed for PbS QD solids treated with thiol-terminating ligands can be prevalently ascribed to 3p orbitals localized on anchoring sulfur atoms, which mix with the highest occupied states of the QDs. More broadly, we provide evidence that organic ligands and inorganic cores are inherently electronically coupled materials thus yielding peculiar chemical species (the colloidal QDs themselves), which display arising (opto)electronic properties that cannot be merely described as the sum of those of the ligand and core components. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2015 holdings: @attributes: islocal: N |
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