TY - JOUR
T1 - Highly (001)-textured p-type WSe2 Thin Films as Efficient Large-Area Photocathodes for Solar Hydrogen Evolution
AU - Bozheyev, Farabi
AU - Harbauer, Karsten
AU - Ellmer, Klaus
N1 - Funding Information:
The authors would like to thank Fanxing Xi for SEM analysis and the ATM deposition, Moritz Kölbach for SEM/ EDX analysis, Paul Plate for XPS, Clark Zahn for TRMC measurements, and Sean Berglund for his help with the PEC measurements. The research association Optotransmitter-Umweltschutz-Technologie e.V. (Berlin, Germany) is acknowledged for the preparation of the TiN:O back contact layers. F.B. acknowledges the Ministry of Education and Science of the Republic of Kazakhstan for a research fellowship under the program no. 0115РК03029 “NU-Berkeley strategic initiative in warm-dense matter, advanced materials and energy sources for 2014–2018” and grants from Tomsk (Russia) Polytechnic University Competitiveness Enhancement Program and National Nanotechnology Laboratory of open type of Al-Farabi Kazakh National University, Almaty (Kazakhstan), 0263/PSF.
PY - 2017/12/1
Y1 - 2017/12/1
N2 - Highly (001)-textured, photoactive WSe2 thin films have been prepared by an amorphous solid-liquid-crystalline solid process promoted by palladium. By increasing the thickness of the Pd promoter film (≥10 nm) the structure and texture of the WSe2 films can be improved significantly. However, these as-crystallized WSe2 films are only weakly photoactive in a 0.5 M H2SO4 electrolyte under AM 1.5 solar irradiation which we attribute to an inefficient photogenerated charge transfer across the WSe2/electrolyte interface via the prevailing van der Waals planes of the WSe2 crystallites. In this work photochemically deposited platinum on the p-type WSe2 photocathode is used for an efficient electron transfer thus inducing the hydrogen evolution reaction. Upon illuminating the WSe2 photocathodes in a Pt-ion containing electrolyte, the photogenerated electrons reduce Pt+ to Pt leading to the precipitation of Pt islands, preferentially at edge steps of the WSe2, i.e. at the grain boundaries of the WSe2 crystallites. The increasing amount of Pt islands at the grain boundaries linearly enhances the photocurrent density up to 2.5 mA cm-2 at 0 VRHE in sulfuric acid, the highest reported value up to now for WSe2 thin films.
AB - Highly (001)-textured, photoactive WSe2 thin films have been prepared by an amorphous solid-liquid-crystalline solid process promoted by palladium. By increasing the thickness of the Pd promoter film (≥10 nm) the structure and texture of the WSe2 films can be improved significantly. However, these as-crystallized WSe2 films are only weakly photoactive in a 0.5 M H2SO4 electrolyte under AM 1.5 solar irradiation which we attribute to an inefficient photogenerated charge transfer across the WSe2/electrolyte interface via the prevailing van der Waals planes of the WSe2 crystallites. In this work photochemically deposited platinum on the p-type WSe2 photocathode is used for an efficient electron transfer thus inducing the hydrogen evolution reaction. Upon illuminating the WSe2 photocathodes in a Pt-ion containing electrolyte, the photogenerated electrons reduce Pt+ to Pt leading to the precipitation of Pt islands, preferentially at edge steps of the WSe2, i.e. at the grain boundaries of the WSe2 crystallites. The increasing amount of Pt islands at the grain boundaries linearly enhances the photocurrent density up to 2.5 mA cm-2 at 0 VRHE in sulfuric acid, the highest reported value up to now for WSe2 thin films.
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U2 - 10.1038/s41598-017-16283-8
DO - 10.1038/s41598-017-16283-8
M3 - Article
AN - SCOPUS:85034808574
VL - 7
JO - Scientific Reports
JF - Scientific Reports
SN - 2045-2322
IS - 1
M1 - 16003
ER -