Perturbation of the Electron Transport Mechanism by Proton Intercalation in Nanoporous TiO2 Films

View Author Information
National Renewable Energy Laboratory, Golden, Colorado 80401-3393, United States
Cite this: Nano Lett. 2012, 12, 4, 2112–2116
Publication Date (Web):March 19, 2012
Copyright © 2012 American Chemical Society
Article Views
Read OnlinePDF (2 MB)
Supporting Info (1)»


This study addresses a long-standing controversy about the electron-transport mechanism in porous metal oxide semiconductor films that are commonly used in dye-sensitized solar cells and related systems. We investigated, by temperature-dependent time-of-flight measurements, the influence of proton intercalation on the electron-transport properties of nanoporous TiO2 films exposed to an ethanol electrolyte containing different percentages of water (0–10%). These measurements revealed that increasing the water content in the electrolyte led to increased proton intercalation into the TiO2 films, slower transport, and a dramatic change in the dependence of the thermal activation energy (Ea) of the electron diffusion coefficient on the photogenerated electron density in the films. Random walk simulations based on a microscopic model incorporating exponential conduction band tail (CBT) trap states combined with a proton-induced shallow trap level with a long residence time accounted for the observed effects of proton intercalation on Ea. Application of this model to the experimental results explains the conditions under which Ea dependence on the photoelectron density is consistent with multiple trapping in exponential CBT states and under which it appears at variance with this model.

Supporting Information

Jump To

Experimental details and additional data. This material is available free of charge via the Internet at

Terms & Conditions

Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system:

Cited By

This article is cited by 40 publications.

  1. Jennifer L. Peper, Noreen E. Gentry, Anna C. Brezny, Mackenzie J. Field, Michael T. Green, James M. Mayer. Different Kinetic Reactivities of Electrons in Distinct TiO2 Nanoparticle Trap States. The Journal of Physical Chemistry C 2021, 125 (1) , 680-690.
  2. Yuhan Lin, Yan Yan, Wei Peng, Xiaofeng Qiao, Di Huang, Hongwei Ji, Chuncheng Chen, Wanhong Ma, Jincai Zhao. Crucial Effect of Ti–H Species Generated in the Visible-Light-Driven Transformations: Slowed-Down Proton-Coupled Electron Transfer. The Journal of Physical Chemistry Letters 2020, 11 (10) , 3941-3946.
  3. Elisabetta Benazzi, Karin Rettenmaier, Thomas Berger, Stefano Caramori, Serena Berardi, Roberto Argazzi, Maurizio Prato, Zois Syrgiannis. Photoelectrochemical Properties of SnO2 Photoanodes Sensitized by Cationic Perylene-Di-Imide Aggregates for Aqueous HBr Splitting. The Journal of Physical Chemistry C 2020, 124 (2) , 1317-1329.
  4. Jennifer L. Peper, James M. Mayer. Manifesto on the Thermochemistry of Nanoscale Redox Reactions for Energy Conversion. ACS Energy Letters 2019, 4 (4) , 866-872.
  5. Solrun Gudjonsdottir, Ward van der Stam, Nicholas Kirkwood, Wiel H. Evers, Arjan J. Houtepen. The Role of Dopant Ions on Charge Injection and Transport in Electrochemically Doped Quantum Dot Films. Journal of the American Chemical Society 2018, 140 (21) , 6582-6590.
  6. William L. Hoffeditz, Michael J. Pellin, Omar K. Farha, and Joseph T. Hupp . Determining the Conduction Band-Edge Potential of Solar-Cell-Relevant Nb2O5 Fabricated by Atomic Layer Deposition. Langmuir 2017, 33 (37) , 9298-9306.
  7. Jennifer L. Peper, David J. Vinyard, Gary W. Brudvig, and James M. Mayer . Slow Equilibration between Spectroscopically Distinct Trap States in Reduced TiO2 Nanoparticles. Journal of the American Chemical Society 2017, 139 (8) , 2868-2871.
  8. Yan Yan, Weidong Shi, Zhen Yuan, Shenggui He, Dongmei Li, Qingbo Meng, Hongwei Ji, Chuncheng Chen, Wanhong Ma, and Jincai Zhao . The Formation of Ti–H Species at Interface Is Lethal to the Efficiency of TiO2-Based Dye-Sensitized Devices. Journal of the American Chemical Society 2017, 139 (5) , 2083-2089.
  9. Nicholas S. McCool, John R. Swierk, Coleen T. Nemes, Timothy P. Saunders, Charles A. Schmuttenmaer, and Thomas E. Mallouk . Proton-Induced Trap States, Injection and Recombination Dynamics in Water-Splitting Dye-Sensitized Photoelectrochemical Cells. ACS Applied Materials & Interfaces 2016, 8 (26) , 16727-16735.
  10. Dhritabrata Mandal and Thomas W. Hamann . Charge Distribution in Nanostructured TiO2 Photoanode Determined by Quantitative Analysis of the Band Edge Unpinning. ACS Applied Materials & Interfaces 2016, 8 (1) , 419-424.
  11. John R. Swierk, Nicholas S. McCool, and Thomas E. Mallouk . Dynamics of Electron Recombination and Transport in Water-Splitting Dye-Sensitized Photoanodes. The Journal of Physical Chemistry C 2015, 119 (24) , 13858-13867.
  12. Qian Zhang, Verónica Celorrio, Kieren Bradley, Flurin Eisner, David Cherns, Wei Yan, and David J. Fermín . Density of Deep Trap States in Oriented TiO2 Nanotube Arrays. The Journal of Physical Chemistry C 2014, 118 (31) , 18207-18213.
  13. John R. Swierk, Nicholas S. McCool, Timothy P. Saunders, Greg D. Barber, and Thomas E. Mallouk . Effects of Electron Trapping and Protonation on the Efficiency of Water-Splitting Dye-Sensitized Solar Cells. Journal of the American Chemical Society 2014, 136 (31) , 10974-10982.
  14. Julio Villanueva-Cab, Song-Rim Jang, Adam F. Halverson, Kai Zhu, and Arthur J. Frank . Trap-Free Transport in Ordered and Disordered TiO2 Nanostructures. Nano Letters 2014, 14 (5) , 2305-2309.
  15. David M. Savory and A. James McQuillan . Influence of Formate Adsorption and Protons on Shallow Trap Infrared Absorption (STIRA) of Anatase TiO2 During Photocatalysis. The Journal of Physical Chemistry C 2013, 117 (45) , 23645-23656.
  16. Fritz J. Knorr and Jeanne L. McHale . Spectroelectrochemical Photoluminescence of Trap States of Nanocrystalline TiO2 in Aqueous Media. The Journal of Physical Chemistry C 2013, 117 (26) , 13654-13662.
  17. Simon C. Boehme, Hai Wang, Laurens D.A. Siebbeles, Daniel Vanmaekelbergh, and Arjan J. Houtepen . Electrochemical Charging of CdSe Quantum Dot Films: Dependence on Void Size and Counterion Proximity. ACS Nano 2013, 7 (3) , 2500-2508.
  18. Yeru Liu, James R. Jennings, Shaik M. Zakeeruddin, Michael Grätzel, and Qing Wang . Heterogeneous Electron Transfer from Dye-Sensitized Nanocrystalline TiO2 to [Co(bpy)3]3+: Insights Gained from Impedance Spectroscopy. Journal of the American Chemical Society 2013, 135 (10) , 3939-3952.
  19. R. Ranjitha, K. N. Meghana, V. G. Dileep Kumar, Aarti S. Bhatt, B. K. Jayanna, C. R. Ravikumar, Mysore Sridhar Santosh, H. Madhyastha, K. Sakai. Rapid photocatalytic degradation of cationic organic dyes using Li-doped Ni/NiO nanocomposites and their electrochemical performance. New Journal of Chemistry 2021, 45 (2) , 796-809.
  20. Robert Godin, James R. Durrant. Dynamics of photoconversion processes: the energetic cost of lifetime gain in photosynthetic and photovoltaic systems. Chemical Society Reviews 2021, 103
  21. Yan Yan, Weidong Shi, Wei Peng, Yuhan Lin, Chunxi Zhang, Lailai Li, Young Sun, Huanxin Ju, Junfa Zhu, Wanhong Ma, Jincai Zhao. Proton-free electron-trapping feature of titanium dioxide nanoparticles without the characteristic blue color. Communications Chemistry 2019, 2 (1)
  22. Li Wang, Merranda Schmid, Justin B. Sambur. Single nanoparticle photoelectrochemistry: What is next?. The Journal of Chemical Physics 2019, 151 (18) , 180901.
  23. Qiuling Ma, Haitao Wang, Huixuan Zhang, Xiuwen Cheng, Mingzheng Xie, Qingfeng Cheng. Fabrication of MnO2/TiO2 nano-tube arrays photoelectrode and its enhanced visible light photoelectrocatalytic performance and mechanism. Separation and Purification Technology 2017, 189 , 193-203.
  24. Jeremy J. Guttman, Conner B. Chambers, Al Rey Villagracia, Gil Nonato C. Santos, Paul R. Berger. Negative differential resistance in polymer tunnel diodes using atomic layer deposited, TiO2 tunneling barriers at various deposition temperatures. Organic Electronics 2017, 47 , 228-234.
  25. Aihua Jia, Miao Kan, Jinping Jia, Yixin Zhao. Photodeposited FeOOH vs electrodeposited Co-Pi to enhance nanoporous BiVO 4 for photoelectrochemical water splitting. Journal of Semiconductors 2017, 38 (5) , 053004.
  26. Pengtao Xu, Nicholas S. McCool, Thomas E. Mallouk. Water splitting dye-sensitized solar cells. Nano Today 2017, 14 , 42-58.
  27. Fredy Nandjou, Sophia Haussener. Degradation in photoelectrochemical devices: review with an illustrative case study. Journal of Physics D: Applied Physics 2017, 50 (12) , 124002.
  28. Meysam Pazoki, Ute B. Cappel, Erik M. J. Johansson, Anders Hagfeldt, Gerrit Boschloo. Characterization techniques for dye-sensitized solar cells. Energy & Environmental Science 2017, 10 (3) , 672-709.
  29. Tao He, Libo Wang, Francisco Fabregat-Santiago, Guoqun Liu, Ying Li, Chong Wang, Rengui Guan. Electron trapping induced electrostatic adsorption of cations: a general factor leading to photoactivity decay of nanostructured TiO 2. Journal of Materials Chemistry A 2017, 5 (14) , 6455-6464.
  30. C. Chiappara, V. Figà, G. Di Marco, G. Calogero, I. Citro, A. Scuto, S. Lombardo, B. Pignataro, F. Principato. Investigation of recovery mechanisms in dye sensitized solar cells. Solar Energy 2016, 127 , 56-66.
  31. Sonia J. Calero, Pablo Ortiz, Andrés F. Oñate, Maria T. Cortés. Effect of proton intercalation on photo-activity of WO3 anodes for water splitting. International Journal of Hydrogen Energy 2016, 41 (9) , 4922-4930.
  32. Xishun Jiang, Qibin Lin, Qingqing Ye, Xianli Xie, Zhongwei Li, Yunfang Ren, Gang He, Zhaoqi Sun. Optical and photoelectron-chemical properties of TiO2 films by using hydrothermal method. Journal of Materials Science: Materials in Electronics 2015, 26 (9) , 6557-6562.
  33. Vasilis Nikolaou, Panagiotis A. Angaridis, Georgios Charalambidis, Ganesh D. Sharma, Athanassios G. Coutsolelos. A “click-chemistry” approach for the synthesis of porphyrin dyads as sensitizers for dye-sensitized solar cells. Dalton Transactions 2015, 44 (4) , 1734-1747.
  34. Wenxing Yang, Meysam Pazoki, Anna I. K. Eriksson, Yan Hao, Gerrit Boschloo. A key discovery at the TiO 2 /dye/electrolyte interface: slow local charge compensation and a reversible electric field. Physical Chemistry Chemical Physics 2015, 17 (26) , 16744-16751.
  35. Jason A. Seabold, Kai Zhu, Nathan R. Neale. Efficient solar photoelectrolysis by nanoporous Mo:BiVO 4 through controlled electron transport. Phys. Chem. Chem. Phys. 2014, 16 (3) , 1121-1131.
  36. Qian Zhang, Ling Wang, Jiangtao Feng, Hao Xu, Wei Yan. Enhanced photoelectrochemical performance by synthesizing CdS decorated reduced TiO 2 nanotube arrays. Phys. Chem. Chem. Phys. 2014, 16 (42) , 23431-23439.
  37. Liping Si, Hongshan He, Kai Zhu. 8-Hydroxylquinoline-conjugated porphyrins as broadband light absorbers for dye-sensitized solar cells. New Journal of Chemistry 2014, 38 (4) , 1565.
  38. Jia Lin, Min Guo, Cho Tung Yip, Wei Lu, Guoge Zhang, Xiaolin Liu, Limin Zhou, Xianfeng Chen, Haitao Huang. High Temperature Crystallization of Free-Standing Anatase TiO 2 Nanotube Membranes for High Efficiency Dye-Sensitized Solar Cells. Advanced Functional Materials 2013, 23 (47) , 5952-5960.
  39. Pegah M. Hosseinpour, Eugen Panaitescu, Don Heiman, Latika Menon, Laura H. Lewis. Toward tailored functionality of titania nanotube arrays: Interpretation of the magnetic-structural correlations. Journal of Materials Research 2013, 28 (10) , 1304-1310.
  40. Wenjing Song, Hanlin Luo, Kenneth Hanson, Javier J. Concepcion, M. Kyle Brennaman, Thomas J. Meyer. Visualization of cation diffusion at the TiO2 interface in dye sensitized photoelectrosynthesis cells (DSPEC). Energy & Environmental Science 2013, 6 (4) , 1240.