Use of interfacial layers to prolong hole lifetimes in hematite probed by ultrafast transient absorption spectroscopy

Show simple item record Paradzah, Alexander Tapera Diale, M. (Mmantsae Moche) Maabong, Kelebogile Kruger, T.P.J. (Tjaart) 2018-06-06T05:28:39Z 2018-04
dc.description.abstract Hematite is a widely investigated material for applications in solar water oxidation due primarily to its small bandgap. However, full realization of the material continues to be hampered by fast electron-hole recombination rates among other weaknesses such as low hole mobility, short hole diffusion length and low conductivity. To address the problem of fast electron-hole recombination, researchers have resorted to growth of nano-structured hematite, doping and use of under-layers. Under-layer materials enhance the photo-current by minimising electron-hole recombination through suppressing of back electron flow from the substrate, such as fluorine-doped tin oxide (FTO), to hematite. We have carried out ultrafast transient absorption spectroscopy on hematite in which Nb2O5 and SnO2 materials were used as interfacial layers to enhance hole lifetimes. The transient absorption data was fit with four different lifetimes ranging from a few hundred femtoseconds to a few nanoseconds. We show that the electron-hole recombination is slower in samples where interfacial layers are used than in pristine hematite. We also develop a model through target analysis to illustrate the effect of under-layers on electron-hole recombination rates in hematite thin films. en_ZA
dc.description.department Physics en_ZA
dc.description.embargo 2019-04-15
dc.description.librarian hj2018 en_ZA
dc.description.sponsorship A.T.P. acknowledges bursaries from the African Laser Centre (ALC) and from the University of Pretoria (UP Postgraduate Research Support Bursary). K.M. acknowledges University of Botswana for financial support. M.D. acknowledges the National Research Foundation (NRF), South Africa, for financial assistance, (National Flagship Programme, Grant number 88021). T.P.J.K. acknowledges the Rental Pool Programme of the National Laser Centre and Department of Science and Technology (Grant number LREJA11), and a grant from the Photonics Initiative of South Africa. en_ZA
dc.description.uri en_ZA
dc.identifier.citation Paradzah, A.T., Diale, M., Maabong, K. & Kruger, T.P.J. 2018, 'Use of interfacial layers to prolong hole lifetimes in hematite probed by ultrafast transient absorption spectroscopy', Physica B : Consensed Matter, vol. 535, pp. 138-142. en_ZA
dc.identifier.issn 0921-4526 (print)
dc.identifier.issn 1873-2135 (online)
dc.identifier.other 10.1016/j.physb.2017.06.088
dc.language.iso en en_ZA
dc.publisher Elsevier en_ZA
dc.rights © 2017 Published by Elsevier B.V. Notice : this is the author’s version of a work that was accepted for publication in Physica B: Consensed Matter. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. A definitive version was subsequently published in Physica B: Consensed Matter, vol. 535, pp. 138-142, 2018. doi : 10.1016/j.physb.2017.06.088. en_ZA
dc.subject Fluorine-doped tin oxide (FTO) en_ZA
dc.subject Oxide thin films en_ZA
dc.subject Photoanodes en_ZA
dc.subject Water oxidation en_ZA
dc.subject Carrier dynamics en_ZA
dc.subject Optical properties en_ZA
dc.subject Photocurrent density en_ZA
dc.subject α-Fe2O3 electrodes en_ZA
dc.subject Photoelectrochemical (PEC) performance en_ZA
dc.subject Nanostructured hematite en_ZA
dc.subject Sol- gel method en_ZA
dc.subject Hematite en_ZA
dc.subject Ultrafast pump-probe spectroscopy en_ZA
dc.subject Under-layer materials en_ZA
dc.subject Stannic oxide (SnO2) en_ZA
dc.subject Niobium oxide (Nb2O5) en_ZA
dc.subject Silicon dioxide (SiO2) en_ZA
dc.title Use of interfacial layers to prolong hole lifetimes in hematite probed by ultrafast transient absorption spectroscopy en_ZA
dc.type Postprint Article en_ZA

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