Geometries, Electronic Structures, And Spectral Properties Of Some Metal Free Phthalonitrile Derivatives For Enhancement Of The Dye Sensitized Solar Cells

Journal Article · Fri Aug 06 00:00:00 EDT 2010 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3482667· OSTI ID:21413506

Anbarasan, P M ^[1]

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1. Department of Physics, Periyar University, Salem-636 011, Tamilnadu (India)

New technologies for direct solar energy conversion have gained more attention in the last few years. In particular, Dye Sensitized Solar Cells (DSSCs) are promising in terms of efficiency and low cost [1,2]. Benefited from systematic device engineering and continuous material innovation, a state of the art DSC with a ruthenium sensitizer has achieved a validated efficiency of 11.1%[3] measured under the air mass 1.5 global (AM1.5G) conditions.The optimized geometries of the 3, 4-Pyridinedicarbonitrile, 3-Aminophthalonitrile, 4-Aminophthalonitrile and 4-Methylphthalonitrile are shown in Fig. 1(a). The frontier molecular orbitals (MO) energies of the dyes 3, 4 Pyridinedicarbonitrile, 3-Nitrophthalonitrile, 4-Aminophthalonitrile and 4-Methylphthalonitrile are shown in Fig. 1(b). The HOMO-LUMO gap of the dye 3, 4 Pyridinedicarbonitrile, 3-Aminophthalonitrile, 4-Aminophthalonitrile and 4-Methylphthalonitrile in vacuum is 5.96 eV, 5.54 eV, 5.57 eV, 5.76 eV respectively. The geometries, electronic structures, polarizabilities, and hyperpolarizabilities of dyes 3, 4-Pyridinedicarbonitrile, 4-Aminophthalonitrile and 4-Methylphthalonitrile were studied by using density functional theory with hybrid functional B3LYP, and the UV-Vis spectra were investigated by using TDDFT methods. The NBO results suggest that 3, 4-Pyridinedicarbonitrile, 3-Aminophthalonitrile 4-Aminophthalonitrile and 4-Methylphthalonitrile are all (D-pi-A) systems. The calculated isotropic polarizability of 3, 4-Pyridinedicarbonitrile, 3-Aminophthalonitrile, 4-Aminophthalonitrile and 4-Methylphthalonitrile is. 85.76, 112.72, 26.63 and 115.13 a.u., respectively. The calculated polarizability anisotropy invariant of 3, 4-Pyridinedicarbonitrile, 3-Aminophthalonitrile, 4-Aminophthalonitrile and 4-Methylphthalonitrile is 74.451, 83.533, 62.653 and 88.526 a.u., respectively. The hyperpolarizabilities of 3, 4-Pyridinedicarbonitrile, 3-Aminophthalonitrile, 4-Aminophthalonitrile and 4-Methylphthalonitrile is 0.80628, 5.60646, 7.7979 and 1.86216 (in a.u.), respectively. The frequencies of strongest IR absorption for 3, 4-Pyridinedicarbonitrile, 3-Aminophthalonitrile, 4-Aminophthalonitrile and 4-Methylphthalonitrile are 1614 cm{sup -1}, 290 cm{sup -1}, 387 cm{sup -1} and 846 cm{sup -1} and the frequencies of strongest Raman activity for 3, 4-Pyridinedicarbonitrile, 3-Aminophthalonitrile, 4-Aminophthalonitrile and 4-Methylphthalonitrile are 2345 cm{sup -1}, 2338 cm{sup -1},2329 cm{sup -1}, 2337cm{sup -1}, respectively. The electronic absorption spectral features in visible and near-UV region were assigned based on the qualitative agreement to TDDFT calculations. The absorptions are all ascribed to {pi}{yields}{pi}* transition. The three excited states with the lowest excited energies of 3, 4-Pyridinedicarbonitrile, 3-Aminophthalonitrile, 4-Aminophthalonitrile and 4-Methylphthalonitrile are photoinduced electron transfer processes that contributes sensitization of photo-to-current conversion processes. The interfacial electron transfer between semiconductor TiO{sub 2} electrode and dye sensitizer 3, 4- Pyridinedicarbonitrile, 3-Aminophthalonitrile, 4-Aminophthalonitrile and 4-Methylphthalonitrile is electron injection process from excited dyes as donor to the semiconductor conduction band. Based on the comparative analysis of geometries, electronic structures, and spectrum properties between 3, 4-Pyridinedicarbonitrile, 3-Aminophthalonitrile, 4-Aminophthalonitrile and 4-Methylphthalonitrile the role of amide and methyl groups in phthalonitrile is as follows: it enlarged the distance between electron donor group and semiconductor surface, and decreased the timescale of the electron injection rate, resulted in giving lower conversion efficiency. This indicates that the choice of the appropriate conjugate bridge in dye sensitizer is very important to enhance the performance of DSSC.

• OSTI ID: 21413506
• Journal Information: AIP Conference Proceedings, Vol. 1267, Issue 1; Conference: 22. international conference on Raman spectroscopy, Boston, MA (United States), 8-10 Aug 2010; Other Information: DOI: 10.1063/1.3482667; (c) 2010 American Institute of Physics; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION
ANISOTROPY
BINDING ENERGY
CALORIMETRY
DENSITY FUNCTIONAL METHOD
DYES
ELECTRON BEAM INJECTION
ELECTRON TRANSFER
ELECTRONIC STRUCTURE
EXCITED STATES
MASS
POLARIZABILITY
SEMICONDUCTOR MATERIALS
SENSITIZERS
SOLAR CELLS
SOLAR ENERGY CONVERSION
SURFACES
TITANIUM OXIDES
ULTRAVIOLET SPECTRA
VISIBLE SPECTRA
BEAM INJECTION
CALCULATION METHODS
CHALCOGENIDES
CONVERSION
DIRECT ENERGY CONVERTERS
ELECTRICAL PROPERTIES
ENERGY
ENERGY CONVERSION
ENERGY LEVELS
EQUIPMENT
MATERIALS
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
REAGENTS
SOLAR EQUIPMENT
SORPTION
SPECTRA
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
VARIATIONAL METHODS