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Title: Bandgap narrowing of titanium oxide semiconductors by non-compensated anion-cation codoping for enhanced visible-light photoactivity

Abstract

Titanium dioxide (TiO2) is widely recognized as one of the most promising photocatalysts for solar energy utilization and environmental cleanup, but because of its wide bandgap, pure TiO2 can only absorbs ultraviolet light, which represents 4% of the solar spectrum1-6. Here we establish a conceptually novel approach, termed non-compensated n-p codoping, to narrow the bandgap of TiO2 and shift the optical response into the visible spectral range where a much larger fraction of the solar spectrum can be captured. The concept embodies two key ingredients: The electrostatic attraction within the n-p dopant pair enhances the thermodynamic and kinetic solubility in substitutional doping, and the non-compensated nature ensures the creation of broadened intermediate electronic states that effectively narrow the bandgap. The concept is demonstrated quantitatively within first-principles density functional theory. The experimental evidence for bandgap narrowing is obtained in the forms of direct measurements of the density of states by scanning tunneling spectroscopy, dramatically redshifted and increased optical absorbance, and enhanced photoactivity manifested by efficient hole-electron separation in the visible spectral region. These findings represent the first crucial steps toward development of a new class of titania-based photocatalysts with greatly enhanced efficiency of solar energy conversion facilitating environmentally friendly applications ofrenewablemore » energy.« less

Authors:
 [1];  [2];  [3];  [3];  [2];  [2];  [4];  [4];  [2];  [2];  [2];  [1];  [2];  [2]
  1. University of Tennessee, Knoxville (UTK)
  2. ORNL
  3. Oak Ridge National Laboratory (ORNL)
  4. Argonne National Laboratory (ANL)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
989117
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 103; Journal Issue: 22; Journal ID: ISSN 0031-9007
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; EFFICIENCY; ELECTROSTATICS; FUNCTIONALS; KINETICS; SOLAR ENERGY; SOLAR ENERGY CONVERSION; SOLUBILITY; SPECTROSCOPY; THERMODYNAMICS; TITANIUM; TITANIUM OXIDES; TUNNELING

Citation Formats

Zhu, Wenguang, Qiu, Xiaofeng, Iancu, Violet, Chen, Xingqiu, Pan, Hui, Wang, Wei, Dimitrijevic, Nada, Rajh, Tijana, Meyer, III, Harry M, Paranthaman, Mariappan Parans, Stocks, George Malcolm, Weitering, Hanno, Gu, Baohua, and Zhang, Zhenyu. Bandgap narrowing of titanium oxide semiconductors by non-compensated anion-cation codoping for enhanced visible-light photoactivity. United States: N. p., 2009. Web. doi:10.1103/PhysRevLett.103.226401.
Zhu, Wenguang, Qiu, Xiaofeng, Iancu, Violet, Chen, Xingqiu, Pan, Hui, Wang, Wei, Dimitrijevic, Nada, Rajh, Tijana, Meyer, III, Harry M, Paranthaman, Mariappan Parans, Stocks, George Malcolm, Weitering, Hanno, Gu, Baohua, & Zhang, Zhenyu. Bandgap narrowing of titanium oxide semiconductors by non-compensated anion-cation codoping for enhanced visible-light photoactivity. United States. https://doi.org/10.1103/PhysRevLett.103.226401
Zhu, Wenguang, Qiu, Xiaofeng, Iancu, Violet, Chen, Xingqiu, Pan, Hui, Wang, Wei, Dimitrijevic, Nada, Rajh, Tijana, Meyer, III, Harry M, Paranthaman, Mariappan Parans, Stocks, George Malcolm, Weitering, Hanno, Gu, Baohua, and Zhang, Zhenyu. 2009. "Bandgap narrowing of titanium oxide semiconductors by non-compensated anion-cation codoping for enhanced visible-light photoactivity". United States. https://doi.org/10.1103/PhysRevLett.103.226401.
@article{osti_989117,
title = {Bandgap narrowing of titanium oxide semiconductors by non-compensated anion-cation codoping for enhanced visible-light photoactivity},
author = {Zhu, Wenguang and Qiu, Xiaofeng and Iancu, Violet and Chen, Xingqiu and Pan, Hui and Wang, Wei and Dimitrijevic, Nada and Rajh, Tijana and Meyer, III, Harry M and Paranthaman, Mariappan Parans and Stocks, George Malcolm and Weitering, Hanno and Gu, Baohua and Zhang, Zhenyu},
abstractNote = {Titanium dioxide (TiO2) is widely recognized as one of the most promising photocatalysts for solar energy utilization and environmental cleanup, but because of its wide bandgap, pure TiO2 can only absorbs ultraviolet light, which represents 4% of the solar spectrum1-6. Here we establish a conceptually novel approach, termed non-compensated n-p codoping, to narrow the bandgap of TiO2 and shift the optical response into the visible spectral range where a much larger fraction of the solar spectrum can be captured. The concept embodies two key ingredients: The electrostatic attraction within the n-p dopant pair enhances the thermodynamic and kinetic solubility in substitutional doping, and the non-compensated nature ensures the creation of broadened intermediate electronic states that effectively narrow the bandgap. The concept is demonstrated quantitatively within first-principles density functional theory. The experimental evidence for bandgap narrowing is obtained in the forms of direct measurements of the density of states by scanning tunneling spectroscopy, dramatically redshifted and increased optical absorbance, and enhanced photoactivity manifested by efficient hole-electron separation in the visible spectral region. These findings represent the first crucial steps toward development of a new class of titania-based photocatalysts with greatly enhanced efficiency of solar energy conversion facilitating environmentally friendly applications ofrenewable energy.},
doi = {10.1103/PhysRevLett.103.226401},
url = {https://www.osti.gov/biblio/989117}, journal = {Physical Review Letters},
issn = {0031-9007},
number = 22,
volume = 103,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 2009},
month = {Thu Jan 01 00:00:00 EST 2009}
}