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Enhanced Photoelectrochemical Water Oxidation from CdTe Photoanodes Annealed with CdCl 2
Author(s) -
Su Jin,
Hisatomi Takashi,
Minegishi Tsutomu,
Domen Kazunari
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202000688
Subject(s) - photocathode , photocurrent , cadmium telluride photovoltaics , photoelectrochemical cell , water splitting , annealing (glass) , reversible hydrogen electrode , materials science , photoelectrochemistry , electrode , energy conversion efficiency , chemistry , optoelectronics , chemical engineering , electrochemistry , electrolyte , photocatalysis , reference electrode , catalysis , electron , biochemistry , physics , quantum mechanics , engineering , composite material
Most CdTe photoanodes and photocathodes show positive and negative photocurrent onset potentials for water oxidation and reduction, respectively, and are thus unable to drive photoelectrochemical (PEC) water splitting without external applied biases. Herein, the activity of a CdTe photoanode having an internal p‐n junction during PEC water oxidation was enhanced by applying a CdCl 2 annealing treatment together with surface modifications. The resulting CdTe photoanode generated photocurrents of 1.8 and 5.4 mA cm −2 at 0.6 and 1.2 V RHE , respectively, with a photoanodic current onset potential of 0.22 V RHE under simulated sunlight (AM 1.5G). The CdCl 2 annealing increased the grain sizes and lowered the density of grain boundaries, allowing more efficient charge separation. Consequently, a two‐electrode tandem PEC cell comprising a CdTe‐based photoanode and photocathode split water without any external bias at a solar‐to‐hydrogen conversion efficiency of 0.51 % at the beginning of the reaction.