TY - JOUR
T1 - Wavelength-Dependent Ultrafast Charge Carrier Separation in the WO3/BiVO4 Coupled System
AU - Grigioni, Ivan
AU - Stamplecoskie, Kevin G.
AU - Jara, Danilo H.
AU - Dozzi, Maria Vittoria
AU - Oriana, Aurelio
AU - Cerullo, Giulio
AU - Kamat, Prashant V.
AU - Selli, Elena
N1 - Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/6/9
Y1 - 2017/6/9
N2 - 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. PEC measurements reveal the implication of these wavelength-dependent ultrafast interactions on the performances of the WO3/BiVO4 heterojunction.
AB - 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. PEC measurements reveal the implication of these wavelength-dependent ultrafast interactions on the performances of the WO3/BiVO4 heterojunction.
UR - http://www.scopus.com/inward/record.url?scp=85029394277&partnerID=8YFLogxK
U2 - 10.1021/acsenergylett.7b00216
DO - 10.1021/acsenergylett.7b00216
M3 - Article
AN - SCOPUS:85029394277
SN - 2380-8195
VL - 2
SP - 1362
EP - 1367
JO - ACS Energy Letters
JF - ACS Energy Letters
IS - 6
ER -