Effect of morphology on electron drift mobility in porous TiO2

Porous titanium dioxide is an attractive material for solar cell application on account of its stability, electron transport properties, and the possibilities for controlling surface morphology as well as for its ease of fabrication and low cost. Nanostructured TiO2 has been intensively studied for...

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Main Authors: B. O. Aduda, P. Ravirajan, K. L. Choy, J. Nelson
Format: Article
Language:English
Published: Wiley 2004-01-01
Series:International Journal of Photoenergy
Online Access:http://dx.doi.org/10.1155/S1110662X04000170
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author B. O. Aduda
P. Ravirajan
K. L. Choy
J. Nelson
author_facet B. O. Aduda
P. Ravirajan
K. L. Choy
J. Nelson
author_sort B. O. Aduda
collection DOAJ
description Porous titanium dioxide is an attractive material for solar cell application on account of its stability, electron transport properties, and the possibilities for controlling surface morphology as well as for its ease of fabrication and low cost. Nanostructured TiO2 has been intensively studied for applications to dye sensitised solar cells. The performance of the titanium dioxide based solar cells is influenced, among other factors, by the electron mobility of the porous titanium dioxide. Different fabrication processes for porous titanium films result in different film morphology, which in turn affects the electron transport. We have employed three different techniques namely, electrostatic spray assisted vapour deposition (ESAVD), D.C. reactive sputtering, and doctor blading of sol-gel dispersions to deposit thin TiO2 films onto indium tin oxide (ITO) coated glass substrates. All these films exhibited only the anatase phase as confirmed by X-ray diffraction analysis. Using the time-of-flight technique, the electron drift mobility in the porous TiO2 films was measured. The results show that in the low field region (< 55,000 V cm−1) the mobility, in all the films, were in the range of 10−7 to 10−6cm2Vs−1. The drift mobility in the films prepared by reactive sputtering was consistently higher than in the films prepared by the two other techniques. Sputter deposited films had lower porosity (∼ 10% and 36% for normal-, and oblique (60∘)-angle deposited films) compared to ∼ 50% for films deposited by the two other techniques. The relationship between the drift mobility and film morphology is discussed with the aid of scanning electron microscopy studies.
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spelling doaj-art-b2bcefcbc0934eab9817c28859751e742025-02-03T06:10:52ZengWileyInternational Journal of Photoenergy1110-662X2004-01-016314114710.1155/S1110662X04000170Effect of morphology on electron drift mobility in porous TiO2B. O. Aduda0P. Ravirajan1K. L. Choy2J. Nelson3Department of Materials, Imperial College London, SW7 2BP, UKCentre for Electronic Materials and Devices, Department of Physics, Imperial College London, SW7 2BZ, UKSchool of Mechanical, Materials, Manufacturing Engineering and Management, University of Nottingham, Nottingham NG7 2RD, UKCentre for Electronic Materials and Devices, Department of Physics, Imperial College London, SW7 2BZ, UKPorous titanium dioxide is an attractive material for solar cell application on account of its stability, electron transport properties, and the possibilities for controlling surface morphology as well as for its ease of fabrication and low cost. Nanostructured TiO2 has been intensively studied for applications to dye sensitised solar cells. The performance of the titanium dioxide based solar cells is influenced, among other factors, by the electron mobility of the porous titanium dioxide. Different fabrication processes for porous titanium films result in different film morphology, which in turn affects the electron transport. We have employed three different techniques namely, electrostatic spray assisted vapour deposition (ESAVD), D.C. reactive sputtering, and doctor blading of sol-gel dispersions to deposit thin TiO2 films onto indium tin oxide (ITO) coated glass substrates. All these films exhibited only the anatase phase as confirmed by X-ray diffraction analysis. Using the time-of-flight technique, the electron drift mobility in the porous TiO2 films was measured. The results show that in the low field region (< 55,000 V cm−1) the mobility, in all the films, were in the range of 10−7 to 10−6cm2Vs−1. The drift mobility in the films prepared by reactive sputtering was consistently higher than in the films prepared by the two other techniques. Sputter deposited films had lower porosity (∼ 10% and 36% for normal-, and oblique (60∘)-angle deposited films) compared to ∼ 50% for films deposited by the two other techniques. The relationship between the drift mobility and film morphology is discussed with the aid of scanning electron microscopy studies.http://dx.doi.org/10.1155/S1110662X04000170
spellingShingle B. O. Aduda
P. Ravirajan
K. L. Choy
J. Nelson
Effect of morphology on electron drift mobility in porous TiO2
International Journal of Photoenergy
title Effect of morphology on electron drift mobility in porous TiO2
title_full Effect of morphology on electron drift mobility in porous TiO2
title_fullStr Effect of morphology on electron drift mobility in porous TiO2
title_full_unstemmed Effect of morphology on electron drift mobility in porous TiO2
title_short Effect of morphology on electron drift mobility in porous TiO2
title_sort effect of morphology on electron drift mobility in porous tio2
url http://dx.doi.org/10.1155/S1110662X04000170
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