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Nano Research 2017, 10(11): 3671-3679 https://doi.org/10.1007/s12274-017-1577-4
Research Article | Issue | Published: 15 June 2017

Surface states in TiO2 submicrosphere films and their effect on electron transport

Show Author's Information Jiawei Zheng1,2,  Li'e Mo1,  Wangchao Chen1,  Ling Jiang1,  Yong Ding3,1,  Zhaoqian Li1,  Linhua Hu1( ),  Songyuan Dai3,1( )
Key Laboratory of Novel Thin Film Solar CellsInstitute of Applied Technology, Hefei Institutes of Physical Science, Chinese Academy of SciencesHefei230088China
University of Science and Technology of ChinaHefei230026China
Beijing Key Laboratory of Novel Thin Film Solar CellsNorth China Electric Power UniversityBeijing102206China
Keywords:
solar cells, surface states, cyclic voltammetry, TiO2 submicrospheres, charge extraction methods
Cite this article:
Zheng J, Mo L, Chen W, et al. Surface states in TiO2 submicrosphere films and their effect on electron transport. Nano Research, 2017, 10(11): 3671-3679. https://doi.org/10.1007/s12274-017-1577-4
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Abstract Full text Electronic supplementary material About this article

Owing to their special three-dimensional network structure and high specific surface area, TiO2 submicrospheres have been widely used as electron conductors in photoanodes for solar cells. In recent years, utilization of TiO2 submicrospheres in solar cells has greatly boosted the photovoltaic performance. Inevitably, however, numerous surface states in the TiO2 network affect electron transport. In this work, the surface states in TiO2 submicrospheres were thoroughly investigated by charge extraction methods, and the results were confirmed by the cyclic voltammetry method. The results showed that ammonia can effectively reduce the number of surface states in TiO2 submicrospheres. Furthermore, in-depth characterizations indicate that ammonia shifts the conduction band toward a more positive potential and improves the interfacial charge transfer. Moreover, charge recombination is effectively prevented. Overall, the cell performance is essentially dependent on the effect of the surface states, which affects the electron transfer and recombination process.


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Electronic supplementary material
About this article

Surface states in TiO2 submicrosphere films and their effect on electron transport

Show Author's information Jiawei Zheng1,2, Li'e Mo1, Wangchao Chen1, Ling Jiang1, Yong Ding3,1, Zhaoqian Li1, Linhua Hu1( ), Songyuan Dai3,1( )
Key Laboratory of Novel Thin Film Solar CellsInstitute of Applied Technology, Hefei Institutes of Physical Science, Chinese Academy of SciencesHefei230088China
University of Science and Technology of ChinaHefei230026China
Beijing Key Laboratory of Novel Thin Film Solar CellsNorth China Electric Power UniversityBeijing102206China

Abstract

Owing to their special three-dimensional network structure and high specific surface area, TiO2 submicrospheres have been widely used as electron conductors in photoanodes for solar cells. In recent years, utilization of TiO2 submicrospheres in solar cells has greatly boosted the photovoltaic performance. Inevitably, however, numerous surface states in the TiO2 network affect electron transport. In this work, the surface states in TiO2 submicrospheres were thoroughly investigated by charge extraction methods, and the results were confirmed by the cyclic voltammetry method. The results showed that ammonia can effectively reduce the number of surface states in TiO2 submicrospheres. Furthermore, in-depth characterizations indicate that ammonia shifts the conduction band toward a more positive potential and improves the interfacial charge transfer. Moreover, charge recombination is effectively prevented. Overall, the cell performance is essentially dependent on the effect of the surface states, which affects the electron transfer and recombination process.

Keywords: solar cells, surface states, cyclic voltammetry, TiO2 submicrospheres, charge extraction methods

References(36)

1

Yu, C. L.; Zhou, W. Q.; Liu, H.; Liu, Y.; Dionysiou, D. D. Design and fabrication of microsphere photocatalysts for environmental purification and energy conversion. Chem. Eng. J. 2016, 287, 117-129.
DOI Google Scholar
2

Jin, J.; Huang, S. Z.; Li, Y.; Tian, H.; Wang, H. E.; Yu, Y.; Chen, L. H.; Hasan, T.; Su, B. L. Hierarchical nanosheet- constructed yolk-shell TiO2 porous microspheres for lithium batteries with high capacity, superior rate and long cycle capability. Nanoscale 2015, 7, 12979-12989.
DOI Google Scholar
3

Huang, Y.; Zhu, J.; Ding, Y.; Chen, S. H.; Zhang, C. N.; Dai, S. Y. TiO2 sub-microsphere film as scaffold layer for efficient perovskite solar cells. ACS Appl. Mater. Interfaces 2016, 8, 8162-8167.
DOI Google Scholar
4

Chen, D. H.; Huang, F. Z.; Cheng, Y. B.; Caruso, R. A. Mesoporous anatase TiO2 beads with high surface areas and controllable pore sizes: A superior candidate for high- performance dye-sensitized solar cells. Adv. Mater. 2009, 21, 2206-2210.
DOI Google Scholar
5

Jung, H. -G.; Kang, Y. S.; Sun, Y. -K. Anatase TiO2 spheres with high surface area and mesoporous structure via a hydrothermal process for dye-sensitized solar cells. Electrochim. Acta 2010, 55, 4637-4641.
DOI Google Scholar
6

Zhang, H. M.; Yu, H.; Han, Y. H.; Liu, P. R.; Zhang, S. Q.; Wang, P.; Cheng, Y. B.; Zhao, H. J. Rutile TiO2 microspheres with exposed nano-acicular single crystals for dye-sensitized solar cells. Nano Res. 2011, 4, 938-947.
DOI Google Scholar
7

Thapa, A.; Zai, J. T.; Elbohy, H.; Poudel, P.; Adhikari, N.; Qian, X. F.; Qiao, Q. Q. TiO2 coated urchin-like SnO2 microspheres for efficient dye-sensitized solar cells. Nano Res. 2014, 7, 1154-1163.
DOI Google Scholar
8

Park, K.; Zhang, Q. F.; Myers, D.; Cao, G. Z. Charge transport properties in TiO2 network with different particle sizes for dye sensitized solar cells. ACS Appl. Mater. Interfaces 2013, 5, 1044-1052.
DOI Google Scholar
9

Kang, S. H.; Kim, J. Y.; Sung, Y. E. Role of surface state on the electron flow in modified TiO2 film incorporating carbon powder for a dye-sensitized solar cell. Electrochim. Acta 2007, 52, 5242-5250.
DOI Google Scholar
10

Bisquert, J.; Vikhrenko, V. S. Interpretation of the time constants measured by kinetic techniques in nanostructured semiconductor electrodes and dye-sensitized solar cells. J. Phys. Chem. B 2004, 108, 2313-2322.
DOI Google Scholar
11

Fabregat-Santiago, F.; Mora-Seró, I.; Garcia-Belmonte, G.; Bisquert, J. Cyclic voltammetry studies of nanoporous semiconductors. Capacitive and reactive properties of nanocrystalline TiO2 electrodes in aqueous electrolyte. J. Phys. Chem. B 2003, 107, 758-768.
DOI Google Scholar
12

Han, L. Y.; Koide, N.; Chiba, Y.; Islam, A.; Mitate, T. Modeling of an equivalent circuit for dye-sensitized solar cells: Improvement of efficiency of dye-sensitized solar cells by reducing internal resistance. CR Chim. 2006, 9, 645-651.
DOI Google Scholar
13

Schlichthörl, G.; Huang, S. Y.; Sprague, J.; Frank, A. J. Band edge movement and recombination kinetics in dye-sensitized nanocrystalline TiO2 solar cells: A study by intensity modulated photovoltage spectroscopy. J. Phys. Chem. B 1997, 101, 8141-8155.
DOI Google Scholar
14

Van de Lagemaat, J.; Park, N. G.; Frank, A. J. Influence of electrical potential distribution, charge transport, and recombination on the photopotential and photocurrent conversion efficiency of dye-sensitized nanocrystalline TiO2 solar cells: A study by electrical impedance and optical modulation techniques. J. Phys. Chem. B 2000, 104, 2044-2052.
DOI Google Scholar
15

Duffy, N. W.; Peter, L. M.; Rajapakse, R. M. G.; Wijayantha, K. G. U. A novel charge extraction method for the study of electron transport and interfacial transfer in dye sensitised nanocrystalline solar cells. Electrochem. Commun. 2000, 2, 658-662.
DOI Google Scholar
16

Wang, M. K.; Anghel, A. M.; Marsan, B.; Cevey Ha, N. -L.; Pootrakulchote, N.; Zakeeruddin, S. M.; Grätzel, M. CoS supersedes Pt as efficient electrocatalyst for triiodide reduction in dye-sensitized solar cells. J. Am. Chem. Soc. 2009, 131, 15976-15977.
DOI Google Scholar
17

Zhang, X.; Yang, Y. X.; Guo, S. Q.; Hu, F. Z.; Liu, L. Mesoporous Ni0.85Se nanospheres grown in situ on graphene with high performance in dye-sensitized solar cells. ACS Appl. Mater. Interfaces 2015, 7, 8457-8464.
DOI Google Scholar
18

Salvalaglio, M.; Vetter, T.; Mazzotti, M.; Parrinello, M. Controlling and predicting crystal shapes: The case of urea. Angew. Chem., Int. Ed. 2013, 125, 13611-13614.
DOI Google Scholar
19

Fàbrega, C.; Monllor-Satoca, D.; Ampudia, S.; Parra, A.; Andreu, T.; Morante, J. R. Tuning the fermi level and the kinetics of surface states of TiO2 nanorods by means of ammonia treatments. J. Phys. Chem. C 2013, 117, 20517-20524.
DOI Google Scholar
20

Chen, W. -C.; Kong, F. -T.; Liu, X. -P.; Guo, F. -L.; Zhou, L.; Ding, Y.; Li, Z. -Q.; Dai, S. -Y. Effect of electron-donor ancillary ligands on the heteroleptic ruthenium complexes: Synthesis, characterization, and application in high-performance dye-sensitized solar cells. Phys. Chem. Chem. Phys. 2016, 18, 11213-11219.
DOI Google Scholar
21

Sugimoto, T.; Kojima, T. Formation mechanism of amorphous TiO2 spheres in organic solvents. 1. Roles of ammonia. J. Phys. Chem. C 2008, 112, 18760-18771.
DOI Google Scholar
22

Bisquert, J.; Fabregat-Santiago, F.; Mora-Seró, I.; Garcia- Belmonte, G.; Barea, E. M.; Palomares, E. A review of recent results on electrochemical determination of the density of electronic states of nanostructured metal-oxide semiconductors and organic hole conductors. Inorg. Chim. Acta 2008, 361, 684-698.
DOI Google Scholar
23

Wang, Q.; Zhang, Z. P.; Zakeeruddin, S. M.; Grätzel, M. Enhancement of the performance of dye-sensitized solar cell by formation of shallow transport levels under visible light illumination. J. Phys. Chem. C 2008, 112, 7084-7092.
DOI Google Scholar
24

Zhang, Z. P.; Zakeeruddin, S. M.; O'Regan, B. C.; Humphry- Baker, R.; Grätzel, M. Influence of 4-guanidinobutyric acid as coadsorbent in reducing recombination in dye-sensitized solar cells. J. Phys. Chem. B 2005, 109, 21818-21824.
DOI Google Scholar
25

Bailes, M.; Cameron, P. J.; Lobato, K.; Peter, L. M. Determination of the density and energetic distribution of electron traps in dye-sensitized nanocrystalline solar cells. J. Phys. Chem. B 2005, 109, 15429-15435.
DOI Google Scholar
26

Peter, L. M.; Duffy, N. W.; Wang, R. L.; Wijayantha, K. G. U. Transport and interfacial transfer of electrons in dye- sensitized nanocrystalline solar cells. J. Electroanal. Chem. 2002, 524-525, 127-136.
DOI Google Scholar
27

Barnes, P. R. F.; Miettunen, K.; Li, X. E.; Anderson, A. Y.; Bessho, T.; Gratzel, M.; O'Regan, B. C. Interpretation of optoelectronic transient and charge extraction measurements in dye-sensitized solar cells. Adv. Mater. 2013, 25, 1881-1922.
DOI Google Scholar
28

Zhu, K.; Kopidakis, N.; Neale, N. R.; van De Lagemaat, J.; Frank, A. J. Influence of surface area on charge transport and recombination in dye-sensitized TiO2 solar cells. J. Phys. Chem. B 2006, 110, 25174-25180.
DOI Google Scholar
29

Ren, X. M.; Feng, Q. Y.; Zhou, G.; Huang, C. H.; Wang, Z. S. Effect of cations in coadsorbate on charge recombination and conduction band edge movement in dye-sensitized solar cells. J. Phys. Chem. C 2010, 114, 7190-7195.
DOI Google Scholar
30

Kou, D. X.; Liu, W. Q.; Hu, L. H.; Dai, S. Y. Cooperative effect of adsorbed cations on electron transport and recombination behavior in dye-sensitized solar cells. Electrochim. Acta 2013, 100, 197-202.
DOI Google Scholar
31

Nelson, J. Continuous-time random-walk model of electron transport in nanocrystalline TiO2 electrodes. Phys. Rev. B 1999, 59, 15374-15380.
DOI Google Scholar
32

Nelson, J.; Haque, S. A.; Klug, D. R.; Durrant, J. R. Trap- limited recombination in dye-sensitized nanocrystalline metal oxide electrodes. Phys. Rev. B 2001, 63, 205321.
DOI Google Scholar
33

Liu, W. Q.; Hu, L. H.; Dai, S. Y.; Guo, L.; Jiang, N. Q.; Kou, D. X. The effect of the series resistance in dye-sensitized solar cells explored by electron transport and back reaction using electrical and optical modulation techniques. Electrochim. Acta 2010, 55, 2338-2343.
DOI Google Scholar
34

Oekermann, T.; Yoshida, T.; Minoura, H.; Wijayantha, K. G. U.; Peter, L. M. Electron transport and back reaction in electrochemically self-assembled nanoporous ZnO/dye hybrid films. J. Phys. Chem. B 2004, 108, 8364-8370.
DOI Google Scholar
35

Ding, Y.; Mo, L. E.; Tao, L.; Ma, Y. M.; Hu, L. H.; Huang, Y.; Fang, X. Q.; Yao, J. X.; Xi, X. W.; Dai, S. Y. TiO2 nanocrystalline layer as a bridge linking TiO2 sub-microspheres layer and substrates for high-efficiency dye-sensitized solar cells. J. Power Sources 2014, 272, 1046-1052.
DOI Google Scholar
36

Chen, W. -C.; Kong, F. -T.; Li, Z. -Q.; Pan, J. -H.; Liu, X. -P.; Guo, F. -L.; Zhou, L.; Huang, Y.; Yu, T.; Dai, S. -Y. Superior light-harvesting heteroleptic ruthenium(Ⅱ) complexes with electron-donating antennas for high performance dye-sensitized solar cells. ACS Appl. Mater. Interfaces 2016, 8, 19410-19417.
DOI Google Scholar
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Publication history
Copyright
Acknowledgements

Publication history

Received: 03 January 2017
Revised: 07 March 2017
Accepted: 09 March 2017
Published: 15 June 2017
Issue date: November 2017

Copyright

© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2017

Acknowledgements

Acknowledgements

This work was supported by the National High-tech R & D Program of China (No. 2015AA050602), the External Cooperation Program of BIC, Chinese Academy of Sciences (No. GJHZ1607), the National Natural Science Foundation of China (Nos. U1205112, 51572080 and 21273242) and Natural Science Foundation of Anhui Province (No. 1508085SMF224).

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