Details
| Original language | English |
|---|---|
| Pages (from-to) | 24282–24291 |
| Number of pages | 10 |
| Journal | Journal of Physical Chemistry C |
| Volume | 121 |
| Issue number | 43 |
| Early online date | 24 Oct 2017 |
| Publication status | Published - 2 Nov 2017 |
Abstract
Charge carrier recombination kinetics of TiO 2 powder samples were analyzed in the time domain ranging from 50 ns to 1 ms. The transient reflectance signals of the charge carriers observed by laser flash photolysis spectroscopy do not fit to simple second order kinetics as expected for the recombination of trapped electrons and holes. The deviation from second order reaction dynamics could rather be explained by the segregation of charge carriers and the fractal dimension of the semiconductor agglomerates. According to the fractal reaction kinetics, the time dependent rate coefficient k f (k f = k 2,ft -h) has been employed instead of the second order rate constant k 2, where the fractal parameter h describes the dimension of the system. This model could successfully be used to describe charge carrier signals in all observed time domains. Moreover, the model was compared with the concept developed by Shuttle et al., which proposes that the charge carrier signals decay following a power-law. The benefits of the fractal model proposed here include the possibility to describe and analyze influences of the morphology on the fractal parameter h and its applicability over a broad range of time domains and excitation energies.
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Energy(all)
- General Energy
- Chemistry(all)
- Physical and Theoretical Chemistry
- Materials Science(all)
- Surfaces, Coatings and Films
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In: Journal of Physical Chemistry C, Vol. 121, No. 43, 02.11.2017, p. 24282–24291.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Fractal Charge Carrier Kinetics in TiO2
AU - Sieland, F.
AU - Schneider, J.
AU - Bahnemann, D.W.
N1 - Funding information: Financial support from the Federal Ministry of Education and Research (BMBF) Project “PureBau” No. 13N13350 is acknowledged. Moreover, we thank KRONOS International, Inc., and Crystal for the TiO2 powders. Additionally, F.S. acknowledges support from the Foundation of German Business (sdw).
PY - 2017/11/2
Y1 - 2017/11/2
N2 - Charge carrier recombination kinetics of TiO 2 powder samples were analyzed in the time domain ranging from 50 ns to 1 ms. The transient reflectance signals of the charge carriers observed by laser flash photolysis spectroscopy do not fit to simple second order kinetics as expected for the recombination of trapped electrons and holes. The deviation from second order reaction dynamics could rather be explained by the segregation of charge carriers and the fractal dimension of the semiconductor agglomerates. According to the fractal reaction kinetics, the time dependent rate coefficient k f (k f = k 2,ft -h) has been employed instead of the second order rate constant k 2, where the fractal parameter h describes the dimension of the system. This model could successfully be used to describe charge carrier signals in all observed time domains. Moreover, the model was compared with the concept developed by Shuttle et al., which proposes that the charge carrier signals decay following a power-law. The benefits of the fractal model proposed here include the possibility to describe and analyze influences of the morphology on the fractal parameter h and its applicability over a broad range of time domains and excitation energies.
AB - Charge carrier recombination kinetics of TiO 2 powder samples were analyzed in the time domain ranging from 50 ns to 1 ms. The transient reflectance signals of the charge carriers observed by laser flash photolysis spectroscopy do not fit to simple second order kinetics as expected for the recombination of trapped electrons and holes. The deviation from second order reaction dynamics could rather be explained by the segregation of charge carriers and the fractal dimension of the semiconductor agglomerates. According to the fractal reaction kinetics, the time dependent rate coefficient k f (k f = k 2,ft -h) has been employed instead of the second order rate constant k 2, where the fractal parameter h describes the dimension of the system. This model could successfully be used to describe charge carrier signals in all observed time domains. Moreover, the model was compared with the concept developed by Shuttle et al., which proposes that the charge carrier signals decay following a power-law. The benefits of the fractal model proposed here include the possibility to describe and analyze influences of the morphology on the fractal parameter h and its applicability over a broad range of time domains and excitation energies.
UR - http://www.scopus.com/inward/record.url?scp=85032800179&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.7b07087
DO - 10.1021/acs.jpcc.7b07087
M3 - Article
VL - 121
SP - 24282
EP - 24291
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 43
ER -