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Title: First principles DFT study of dye-sensitized CdS quantum dots

Dye-sensitized quantum dots (QDs) are considered promising candidates for dye-sensitized solar cells. In order to maximize their efficiency, detailed theoretical studies are important. Here, we report a first principles density functional theory (DFT) investigation of experimentally realized dye - sensitized QD / ligand systems, viz., Cd{sub 16}S{sub 16}, capped with acetate molecules and a coumarin dye. The hybrid B3LYP functional and a 6−311+G(d,p)/LANL2dz basis set are used to study the geometric, energetic and electronic properties of these clusters. There is significant structural rearrangement in all the clusters studied - on the surface for the bare QD, and in the positions of the acetate / dye ligands for the ligated QDs. The density of states (DOS) of the bare QD shows states in the band gap, which disappear on surface passivation with the acetate molecules. Interestingly, in the dye-sensitised QD, the HOMO is found to be localized mainly on the dye molecule, while the LUMO is on the QD, as required for photo-induced electron injection from the dye to the QD.
Authors:
;  [1] ;  [2] ; ;  [3] ;  [4]
  1. Department of Physics, D. J. College, Baraut -250611, U.P. (India)
  2. Department of Chemistry, J. V. College, Baraut -250611, U.P. (India)
  3. Fysikum, Albanova University Center, Stockholm University, S-106 91 Stockholm (Sweden)
  4. High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)
Publication Date:
OSTI Identifier:
22269516
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1591; Journal Issue: 1; Conference: 58. DAE solid state physics symposium 2013, Patiala, Punjab (India), 17-21 Dec 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 77 NANOSCIENCE AND NANOTECHNOLOGY; ACETATES; CADMIUM SULFIDES; COUMARIN; DENSITY FUNCTIONAL METHOD; DYES; ELECTRON BEAM INJECTION; ELECTRONIC STRUCTURE; ENERGY GAP; ENERGY-LEVEL DENSITY; LIGANDS; MOLECULAR CLUSTERS; MOLECULES; QUANTUM DOTS; SOLAR CELLS