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Title: Charge separation in solid-state dye-sensitized heterojunction solar cells

Abstract

Dye-sensitized nanocrystalline solar cells are presently under intensive investigation, as they offer an attractive alternative to conventional p--n junction devices. Solid-state versions have been described where the electrolyte present in the pores of the malodorous oxide film is replaced by a large band gap p-type semiconductor. In this way, a solid-state heterojunction of very large contact area is formed. Light is absorbed by the dye that is located at the interface. Upon excitation, the dye injects electrons into the conduction band of the oxide and is regenerated by hole injection into the p-type conductor. High incident photon-to-electric current conversion efficiencies have been achieved recently with a cell consisting of a dye-derivatized mesoporous TiO{sub 2} film contacted by a new organic hole conductor. The great advantage of such systems with regard to conventional p--n junctions is that only majority carriers are involved in the photoelectric conversion process. Moreover, these are generated by the dye precisely at the site of the junction where the electric field is maximal, enhancing charge separation. Photoelectric conversion by conventional solar cells involves minority carriers whose lifetime is restricted due to recombination. As they are generated throughout the semiconductor and away from the junction, expensive high-purity materialsmore » are required in order to maintain the minority carrier diffusion length at a level where current losses are avoided. While the dynamics of photoinduced redo processes in photoelectrochemical systems have been studied in great detail, little is known about the electron-transfer dynamics in solid-state sensitized junctions. Here the authors report for the first time on the direct observation of photoinduced, interfacial charge separation across a dye-sensitized solid-state heterojunction by means of picosecond transient absorption laser spectroscopy.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Swiss Federal Inst. of Tech., Lausanne (CH)
OSTI Identifier:
20000037
Resource Type:
Journal Article
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 121; Journal Issue: 32; Other Information: PBD: 18 Aug 1999; Journal ID: ISSN 0002-7863
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; SOLAR CELLS; HETEROJUNCTIONS; ELECTRON TRANSFER; DYES; LASER SPECTROSCOPY

Citation Formats

Bach, U., Tachibana, Yasuhiro, Moser, J.E., Haque, S.A., Durrant, J.R., Graetzel, M., and Klug, D.R. Charge separation in solid-state dye-sensitized heterojunction solar cells. United States: N. p., 1999. Web. doi:10.1021/ja9915403.
Bach, U., Tachibana, Yasuhiro, Moser, J.E., Haque, S.A., Durrant, J.R., Graetzel, M., & Klug, D.R. Charge separation in solid-state dye-sensitized heterojunction solar cells. United States. doi:10.1021/ja9915403.
Bach, U., Tachibana, Yasuhiro, Moser, J.E., Haque, S.A., Durrant, J.R., Graetzel, M., and Klug, D.R. Wed . "Charge separation in solid-state dye-sensitized heterojunction solar cells". United States. doi:10.1021/ja9915403.
@article{osti_20000037,
title = {Charge separation in solid-state dye-sensitized heterojunction solar cells},
author = {Bach, U. and Tachibana, Yasuhiro and Moser, J.E. and Haque, S.A. and Durrant, J.R. and Graetzel, M. and Klug, D.R.},
abstractNote = {Dye-sensitized nanocrystalline solar cells are presently under intensive investigation, as they offer an attractive alternative to conventional p--n junction devices. Solid-state versions have been described where the electrolyte present in the pores of the malodorous oxide film is replaced by a large band gap p-type semiconductor. In this way, a solid-state heterojunction of very large contact area is formed. Light is absorbed by the dye that is located at the interface. Upon excitation, the dye injects electrons into the conduction band of the oxide and is regenerated by hole injection into the p-type conductor. High incident photon-to-electric current conversion efficiencies have been achieved recently with a cell consisting of a dye-derivatized mesoporous TiO{sub 2} film contacted by a new organic hole conductor. The great advantage of such systems with regard to conventional p--n junctions is that only majority carriers are involved in the photoelectric conversion process. Moreover, these are generated by the dye precisely at the site of the junction where the electric field is maximal, enhancing charge separation. Photoelectric conversion by conventional solar cells involves minority carriers whose lifetime is restricted due to recombination. As they are generated throughout the semiconductor and away from the junction, expensive high-purity materials are required in order to maintain the minority carrier diffusion length at a level where current losses are avoided. While the dynamics of photoinduced redo processes in photoelectrochemical systems have been studied in great detail, little is known about the electron-transfer dynamics in solid-state sensitized junctions. Here the authors report for the first time on the direct observation of photoinduced, interfacial charge separation across a dye-sensitized solid-state heterojunction by means of picosecond transient absorption laser spectroscopy.},
doi = {10.1021/ja9915403},
journal = {Journal of the American Chemical Society},
issn = {0002-7863},
number = 32,
volume = 121,
place = {United States},
year = {1999},
month = {8}
}