title: Light absorption engineering of a hybrid (Sn3S72-)nbased semiconductor - from violet to red light absorption.
abstract: The crystalline two-dimensional thiostannate Sn3S7(trenH)2[tren = tris(2-aminoethyl)amine] consists of negatively charged (Sn3S72-)npolymeric sheets with trenH+molecular species embedded in-between. The semiconducting compound is a violet light absorber with a band gap of 3.0 eV. In this study the compound was synthesized and functionalized by introducing the cationic dyes Methylene Blue (MB) or Safranin T (ST) into the crystal structure by ion exchange. Dye capacities up to approximately 45 mg/g were obtained, leading to major changes of the light absorption properties of the dye stained material. Light absorption was observed in the entire visible light region from red to violet, the red light absorption becoming more substantial with increasing dye content. The ion exchange reaction was followed in detail by variation of solvent, temperature and dye concentration. Time-resolved studies show that the ion exchange follows pseudo-second order kinetics and a Langmuir adsorption mechanism. The pristine and dye stained compounds were characterized by powder X-ray diffraction and scanning electron microscopy revealing that the honeycomb hexagonal pore structure of the host material was maintained by performing the ion exchange in the polar organic solvent acetonitrile, while reactions in water caused a break-down of the long-range ordered structure.
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.
authors.forename: Mathias Salomon
authors.initials: MS
authors.lastname: Hvid
authors.affiliation: Carbon Dioxide Activation Center (CADIAC), Interdisciplinary Nanoscience Center (iNANO); Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.
authors.forename: Paolo
authors.initials: P
authors.lastname: Lamagni
authors.affiliation: Carbon Dioxide Activation Center (CADIAC), Interdisciplinary Nanoscience Center (iNANO); Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.
authors.forename: Nina
authors.initials: N
authors.lastname: Lock