Nanocrystalline dye sensitized solar cells

Figure 11 Illustration of the interfacial CT processes in a nanocrystalline dye-sensitized solar cell. S / S+/S represent the sensitizer in the ground, oxidized and excited state, respectively. Visible light absorption by the sensitizer (1) leads to an excited state, followed by electron injection (2) onto the conduction band of Ti02. The oxidized sensitizer (3) is reduced by the I-/I3 redox couple (4) The injected electrons into the conduction band may react either with the oxidized redox couple (5) or with an oxidized dye molecule (6).

Liska P., Thampi K. R., Gratzel M., Bremaud D., Rudmann D. and Upadhyaya H. M. (2006), Nanocrystalline dye-sensitized solar cell/copper indium gallium selenide thin-fdm tandem showing greater than 15% conversion efficiency , Appl. Phys. Lett. 88, 203103-203106. 

Wang P., Klein C., Humphry-Baker R., Zakeeruddin S. M. and Gratzel M. (2005b), Stable 8% efficient nanocrystalline dye-sensitized solar cell based on an electrolyte of low volatility , Appl. Phys. Lett. 86, 1235081-1235083. 

Tributsch, H. (2001), Function and analytical formula for nanocrystalline dye-sensitization solar cells, Appl. Phys. A 73, 305-316... 

M. Gratzel, Conversion of sunlight to electric power hy nanocrystalline dye-sensitized solar cells . Journal of Photochemistry and Photohiology A Chemistry, 164, 3-14, (2004). 

Nazeeruddin MdK, Humphry-Baker R, Officer DL, Campbell WM, Burrell AK, Gratzel M (2004) Application of metalloporphyrins in nanocrystalline dye-sensitized solar cells for conversion of sunlight into electricity. Langmuir 20 6514-6517... 

Cameron PJ, Peter LM (2005) How does back-reaction at the conducting glass substrate influoice the dynamic photovoltage response of nanocrystalline dye-sensitized solar cells J Phys Chem B 109 7392... 

The experimental strategy of this project consisted in fabrication of standard nanocrystalline dye sensitized solar cells like those now produced in many laboratories [19, 37, 38]. The cells were operated with 6 different sensitizers, which were selected as the most efficient from a larger number of dyes previously used. Both, cells made of nanocrystalline ZnO and TiO were compared, and the time-de-pendent performance of dye sensitized cells investigated by observing their photo-electrochemical performance and studying space resolved photocurrent images in order to distinguish the performance of illuminated and nonilluminated areas. 

Xie, P. Guo, F., Molecular design of ruthenium complexes for dye-sensitized solar cells based on nanocrystalline Ti02. Current Org. Chem. 2011,15 3849-3869. 

Kay A (1996) Low cost photovoltaic modules based on dye sensitized nanocrystalline titanium dioxide and carbon powder. Solar Energy Mater Solar Cells 44 99-117 Wang X, Zhi L, Muellen K (2008) Transparent, conductive graphene electrodes for dye-sensitized solar cells. Nano Lett 8 323-327... 

Dye-sensitized solar cells (DSSCs) are photoelectrochemical solar devices, currently subject of intense research in the framework of renewable energies as a low-cost photovoltaic device. DSSCs are based upon the sensitization of mesoporous nanocrystalline metal oxide films to visible light by the adsorption of molecular dyes.5"7 Photoinduced electron injection from the sensitizer dye (D) into the metal oxide conduction band initiates charge separation. Subsequently, the injected electrons are transported through the metal oxide film to a transparent electrode, while a redox-active electrolyte, such as I /I , is employed to reduce the dye cation and transport the resulting positive charge to a counter electrode (Fig. 17.4). 

DSSCs efficiencies up to 10.4%8 have been reported for devices employing nanocrystalline Ti02 films. Several studies have addressed the use of alternative metal oxides including SnCU,9 10 ZnO,11,12 and Nb205.13 The performance of dye-sensitized solar cells can be understood in view of the kinetic competition among the various redox processes involved in the conversion of light into electricity. Ultrafast electron injection (k2) has been observed in the femtosecond-picosecond (10 l5-... 

Briefly, we describe here various steps involved in the preparation of dye-sensitized solar cell. The nanocrystalline TiO2 prepared by depositing TiO2... 

The other important aspect in dye-sensitized solar cells is water-induced desorption of the sensitizer from the TiC>2 surface. Extensive efforts have been made in our laboratory to overcome this problem by introducing hydrophobic properties in the ligands 13-17. The absorption spectra of these complexes show broad features in the visible region and display maxima around 530 nm. The performance of these hydrophobic complexes as charge transfer photosensitizers in nanocrystalline TiC>2-based solar cells shows excellent stability towards water-induced desorption [36]. 

An, H. J., Jang, S. R., Vittal, R., Lee, J. and Kim, K. J. (2005). Cationic surfactant promoted reductive electrodeposition of nanocrystalline anatase Ti02 for application to dye-sensitized solar cells. Electrochimica Acta 50(13), 2713-2718. 

Zhang, D. S., Yoshida, T. and Minoura, H. (2002). Low temperature synthesis of porous nanocrystalline Ti02 thick film for dye-sensitized solar cells by hydrothermal crystallization. Chem. Lett. (9), 874-875. 

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