Determination of the effective diffusion constant of I/sub 3//sup -/ ions in nanoporous TiO/sub 2/ networks

Author

Kron, G. ; Rau, U. ; Taretto, K. ; Durr, M. ; Miteva, T. ; Nelles, G. ; Yasuda, A. ; Werner, J.H.

Author_Institution

Inst. of Phys. Electron., Stuttgart Univ., Germany

Volume

1

fYear

2003

fDate

18-18 May 2003

Firstpage

133

Abstract

A device structure similar to the dye sensitized solar cells is investigated by current/voltage measurements. Using a platinum front electrode directly in contact to the nanoporous TiO/sub 2/ layer, we find diffusion limitation due to triiodide I/sub 3//sup -/. From the value of the maximum current density we calculate the I/sub 3//sup -/ diffusion constant D/sub T/ in a nanoporous medium. In addition, we evaluate a quantitative model to describe the complete I/V-characteristic of the device. Fitting the model to the experimental data we deduce a diffusion constant for I/sub 3//sup -/ of D/sub T/ = 1.24 (/spl plusmn/ 0.02)/spl times/10/sup -5/ cm/sup 2/s/sup -1/ in the bulk of the electrolyte and an effective diffusion constant of D/sub T//sup eff/ = 0.44 (/spl plusmn/ 0.02)/spl times/10/sup -5/ cm/sup 2/s/sup -1/ within the pores of the TiO/sub 2/ network.

Keywords

current density; diffusion; electrolytes; iodine; nanoporous materials; platinum; semiconductor materials; solar cells; titanium compounds; TiO/sub 2/-Pt-I/sub 3/; current-voltage measurement; diffusion limitation; dye sensitized solar cell; effective diffusion constant; electrolyte; maximum current density; nanoporous TiO/sub 2/ network; platinum front electrode; quantitative model;

fLanguage

English

Publisher

ieee

Conference_Titel

Photovoltaic Energy Conversion, 2003. Proceedings of 3rd World Conference on

Conference_Location

Osaka, Japan

Print_ISBN

4-9901816-0-3

Type

conf

Filename

1305238