Hybridized electronic states between CdSe nanoparticles and conjugated organic ligands: A theoretical and ultrafast photo-excited carrier dynamics study

  • Tersilla Virgili
  • Arrigo Calzolari
  • Inma Suárez López
  • Alice Ruini
  • Alessandra Catellani
  • Barbara Vercelli
  • Francesco Tassone
Research Article

Abstract

Formation of densely packed thin films of semiconductor nanocrystals is advantageous for the exploitation of their unique optoelectronic properties for real-world applications. Here we investigate the fundamental role of the structure of the bridging ligand on the optoelectronic properties of the resulting hybrid film. In particular, we considered hybrid films formed using the same CdSe nanocrystals and two organic ligands that have the same bidentate dithiocarbamate binding moiety, but differ in their bridging structures, one bridged by ethylene, the other by phenylene that exhibits conjugation. Based on the results of photo-excited carrier dynamics experiments combined with theoretical calculations on the electronic states of bridged CdSe layers, we show that only the phenylene-based ligand presents a strong hybridization of the molecular HOMO state with CdSe layers, that is a marker of formation of an effective bridge. We argue that this hybridization spread favors the hopping of photo-excited carriers between nanocrystals, which may explain the reported larger photo-currents in phenylene-based hybrid films than those observed in ethylene-based ones.

Keywords

hybrid layer-by-layer film ultrafast spectroscopy CdSe nanoparticles molecular orbitals density functional theory 

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Hybridized electronic states between CdSe nanoparticles and conjugated organic ligands: A theoretical and ultrafast photo-excited carrier dynamics study

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Copyright information

© Tsinghua University Press and Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  • Tersilla Virgili
    • 1
  • Arrigo Calzolari
    • 2
  • Inma Suárez López
    • 1
  • Alice Ruini
    • 2
    • 3
  • Alessandra Catellani
    • 2
  • Barbara Vercelli
    • 4
  • Francesco Tassone
    • 5
  1. 1.IFN–CNR, c\o Dipartimento di Fisica Politecnico di MilanoMilanoItaly
  2. 2.Istituto Nanoscienze CNR-NANO-S3ModenaItaly
  3. 3.Dipartimento di Scienze Fisiche, Informatiche e MatematicheUniversità di Modena e Reggio EmiliaModenaItaly
  4. 4.Istituto di Chimica della Materia Condensata e di Tecnologie per l’EnergiaICMATE-CNR SS di MilanoMilanoItaly
  5. 5.Center for Nano Science and Technology @PolimiIstituto Italiano di TecnologiaMilanoItaly

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