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Improvement of Solar Energy Conversion with Nb‐Incorporated TiO 2 Hierarchical Microspheres
Author(s) -
Hoang Son,
Ngo Thong Q.,
Berglund Sean P.,
Fullon Raymond R.,
Ekerdt John G.,
Mullins C. Buddie
Publication year - 2013
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201201092
Subject(s) - anatase , dye sensitized solar cell , materials science , niobium , rutile , nanowire , nanoparticle , nanotechnology , chemical engineering , photocatalysis , energy conversion efficiency , electrode , optoelectronics , catalysis , chemistry , biochemistry , engineering , electrolyte , metallurgy
Niobium‐modified TiO 2 hierarchical spherical micrometer‐size particles, which consist of many nanowires, are synthesized by solvothermal synthesis and studied as photoelectrodes for water photo‐oxidation and dye‐sensitized solar cell (DSSC) applications. Incorporation of Nb leads to a rutile‐to‐anatase TiO 2 phase transition in the TiO 2 hierarchical spheres (HSs), with the anatase percentage increasing from 0 % for the pristine TiO 2 HSs to 47.6 % for the 1.82 at. % Nb‐incorporated TiO 2 sample. Incorporation of Nb leads to significant improvements in water photo‐oxidation with the photocurrents reaching 70.5 μA cm −2 at 1.23 V versus the reversible hydrogen electrode, compared with 28.3 μA cm −2 for the pristine TiO 2 sample. The photoconversion efficiency of Nb:TiO 2 HS‐based DSSCs reaches 6.09±0.15 % at 0.25 at. % Nb, significantly higher than that for the pristine TiO 2 HS cells (3.99±0.02 %). In addition, the incident‐photon‐to‐current efficiency spectra for DSSCs show that employing TiO 2 and Nb:TiO 2 HSs provides better light harvesting, especially of long‐wavelength photons, than anatase TiO 2 nanoparticle‐based DSSCs.