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Ge‐Mediated Modification in Ta 3 N 5 Photoelectrodes with Enhanced Charge Transport for Solar Water Splitting
Author(s) -
Feng Jianyong,
Cao Dapeng,
Wang Zhiqiang,
Luo Wenjun,
Wang Jiajia,
Li Zhaosheng,
Zou Zhigang
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201402760
Subject(s) - photocurrent , water splitting , materials science , band gap , electron transport chain , analytical chemistry (journal) , charge carrier , irradiation , optoelectronics , chemistry , photocatalysis , physics , biochemistry , nuclear physics , catalysis , chromatography
Ta 3 N 5 is a promising photoanode candidate for photoelectrochemical water splitting, with a band gap of about 2.1 eV and a theoretical solar‐to‐hydrogen efficiency as high as 15.9 % under AM 1.5 G 100 mW cm −2 irradiation. However, the presently achieved highest photocurrent (ca. 7.5 mA cm −2 ) on Ta 3 N 5 photoelectrodes under AM 1.5 G 100 mW cm −2 is far from the theoretical maximum (ca. 12.9 mA cm −2 ), which is possibly due to serious bulk recombination (poor bulk charge transport and charge separation) in Ta 3 N 5 photoelectrodes. In this study, we show that volatilization of intentionally added Ge (5 %) during the synthesis of Ta 3 N 5 promotes the electron transport and thereby improves the charge‐separation efficiency in bulk Ta 3 N 5 photoanode, which affords a 320 % increase of the highest photocurrent comparing with that of pure Ta 3 N 5 photoanode under AM 1.5 G 100 mW cm −2 simulated sunlight.