title: DFT and TD-DFT study on geometries, electronic structures and electronic absorption of some metal free dye sensitizers for dye sensitized solar cells.
abstract: The geometries, electronic structures, polarizabilities and hyperpolarizabilities of 2-hydroxynaphthalene-1,4-dione (henna1), 3-(5-((1E)-2-(1,4-dihydro-1,4-dioxonaphthalen-3-yloxy) vinyl) thiophen-2-yl)-2-isocyanoacrylic acid (henna2) and anthocyanin dye sensitizers were studied based on density functional theory (DFT) using the hybrid functional B3LYP. The Ultraviolet-Visible (UV-Vis) spectrum was investigated by using a hybrid method which combines the properties and dynamics of many-body in the presence of time-dependent (TD) potentials, i.e. TDSCF-DFT (B3LYP). Features of the electronic absorption spectrum in the visible and near-UV regions were plotted and assigned based on TD-DFT calculations. Due to the absorption, bands of the metal-organic compound are n→π(*) present. The calculated results suggest that the three lowest energy excited states of the investigated dye sensitizers are due to photoinduced electron transfer processes. The interfacial electron transfer between semiconductor TiO2 electrode and dye sensitizer is owing to an electron injection process from excited dye to the semiconductor's conduction band. The role of linking the henna1 dye with a carboxylic acid via a thiophene bridge was analyzed. The results are that using a stronger π-conjugate bridge as well as a strong donator and acceptor group enhances the efficiency.
authors.affiliation: Mahendra Educational Institutions, Mahendhirapuri, Mallasamudram, Namakkal District, Tamil Nadu, India; Department of Energy and Drive Systems, University of Applied Sciences, Ulm, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Mohr
authors.affiliation: Mahendra Educational Institutions, Mahendhirapuri, Mallasamudram, Namakkal District, Tamil Nadu, India.
authors.forename: V
authors.initials: V
authors.lastname: Aroulmoji
authors.affiliation: Mahendra Educational Institutions, Mahendhirapuri, Mallasamudram, Namakkal District, Tamil Nadu, India.
authors.forename: R Samson
authors.initials: RS
authors.lastname: Ravindran
authors.affiliation: Department of Energy and Drive Systems, University of Applied Sciences, Ulm, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Müller
authors.affiliation: Velalar College of Engineering and Technology, Thindal, Erode, Tamil Nadu, India.
authors.forename: S
authors.initials: S
authors.lastname: Ranjitha
authors.affiliation: Mahendra Educational Institutions, Mahendhirapuri, Mallasamudram, Namakkal District, Tamil Nadu, India.
authors.forename: G
authors.initials: G
authors.lastname: Rajarajan
authors.affiliation: Department of Physics, Periyar University, Salem, Tamil Nadu, India.
authors.forename: P M
authors.initials: PM
authors.lastname: Anbarasan
mesh_terms: D065966:Absorption, Physicochemical; D000097:Acetonitriles / Q000737:chemistry; D004396:Coloring Agents / Q000737:chemistry*; D004583:Electrons; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D012993:Solar Energy; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics; D013997:Time Factors
chemical_list: D000097:Acetonitriles; D004396:Coloring Agents; D008670:Metals; D012997:Solvents; C032159:acetonitrile
keywords: Absorption spectrum; DFT and TD-DFT; DSSC; Dye sensitizer; Geometric structure; HOMO and LUMO orbitals