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Title: Wavelength-dependent ultrafast charge carrier separation in the WO 3/BiVO 4 coupled system

Due to its ~2.4 eV band gap, BiVO 4 is a very promising photoanode material for harvesting the blue portion of the solar light for photoelectrochemical (PEC) water splitting applications. In WO 3/BiVO 4 heterojunction films, the electrons photoexcited in BiVO 4 are injected into WO 3, overcoming the lower charge carriers’ diffusion properties limiting the PEC performance of BiVO 4 photoanodes. Here, we investigate by ultrafast transient absorption spectroscopy the charge carrier interactions occurring at the interface between the two oxides in heterojunction systems to directly unveil their wavelength dependence. Under selective BiVO 4 excitation, a favorable electron transfer from photoexcited BiVO 4 to WO 3 occurs immediately after excitation and leads to an increase of the trapped holes’ lifetime in BiVO4. However, a recombination channel opens when both oxides are simultaneously excited, evidenced by a shorter lifetime of trapped holes in BiVO 4. As a result, PEC measurements reveal the implication of these wavelength-dependent ultrafast interactions on the performances of the WO 3/BiVO 4 heterojunction.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [4] ;  [4] ; ORCiD logo [3] ; ORCiD logo [1]
  1. Univ. degli Studi di Milano, Milano (Italy)
  2. Queen's Univ., Kingston, ON (Canada)
  3. Univ. of Notre Dame, Notre Dame, IN (United States)
  4. Politecnico di Milano, Milano (Italy)
Publication Date:
Grant/Contract Number:
FC02-04ER15533
Type:
Published Article
Journal Name:
ACS Energy Letters
Additional Journal Information:
Journal Volume: 2; Journal Issue: 6; Journal ID: ISSN 2380-8195
Publisher:
American Chemical Society (ACS)
Research Org:
Univ. of Notre Dame, Notre Dame, IN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE
OSTI Identifier:
1356719
Alternate Identifier(s):
OSTI ID: 1372220

Grigioni, Ivan, Stamplecoskie, Kevin G., Jara, Danilo H., Dozzi, Maria Vittoria, Oriana, Aurelio, Cerullo, Giulio, Kamat, Prashant V., and Selli, Elena. Wavelength-dependent ultrafast charge carrier separation in the WO3/BiVO4 coupled system. United States: N. p., Web. doi:10.1021/acsenergylett.7b00216.
Grigioni, Ivan, Stamplecoskie, Kevin G., Jara, Danilo H., Dozzi, Maria Vittoria, Oriana, Aurelio, Cerullo, Giulio, Kamat, Prashant V., & Selli, Elena. Wavelength-dependent ultrafast charge carrier separation in the WO3/BiVO4 coupled system. United States. doi:10.1021/acsenergylett.7b00216.
Grigioni, Ivan, Stamplecoskie, Kevin G., Jara, Danilo H., Dozzi, Maria Vittoria, Oriana, Aurelio, Cerullo, Giulio, Kamat, Prashant V., and Selli, Elena. 2017. "Wavelength-dependent ultrafast charge carrier separation in the WO3/BiVO4 coupled system". United States. doi:10.1021/acsenergylett.7b00216.
@article{osti_1356719,
title = {Wavelength-dependent ultrafast charge carrier separation in the WO3/BiVO4 coupled system},
author = {Grigioni, Ivan and Stamplecoskie, Kevin G. and Jara, Danilo H. and Dozzi, Maria Vittoria and Oriana, Aurelio and Cerullo, Giulio and Kamat, Prashant V. and Selli, Elena},
abstractNote = {Due to its ~2.4 eV band gap, BiVO4 is a very promising photoanode material for harvesting the blue portion of the solar light for photoelectrochemical (PEC) water splitting applications. In WO3/BiVO4 heterojunction films, the electrons photoexcited in BiVO4 are injected into WO3, overcoming the lower charge carriers’ diffusion properties limiting the PEC performance of BiVO4 photoanodes. Here, we investigate by ultrafast transient absorption spectroscopy the charge carrier interactions occurring at the interface between the two oxides in heterojunction systems to directly unveil their wavelength dependence. Under selective BiVO4 excitation, a favorable electron transfer from photoexcited BiVO4 to WO3 occurs immediately after excitation and leads to an increase of the trapped holes’ lifetime in BiVO4. However, a recombination channel opens when both oxides are simultaneously excited, evidenced by a shorter lifetime of trapped holes in BiVO4. As a result, PEC measurements reveal the implication of these wavelength-dependent ultrafast interactions on the performances of the WO3/BiVO4 heterojunction.},
doi = {10.1021/acsenergylett.7b00216},
journal = {ACS Energy Letters},
number = 6,
volume = 2,
place = {United States},
year = {2017},
month = {5}
}