Iron-Treated NiO as a Highly Transparent p-Type Protection Layer for Efficient Si-Based Photoanodes.
Sputter deposition of 50 nm thick NiO films on p(+)-n-Si and subsequent treatment in an Fe-containing electrolyte yielded highly transparent photoanodes capable of water oxidation (OER) in alkaline media (1 M KOH) with high efficiency and stability. The Fe treatment of NiO thin films enabled Si-based photoanode assemblies to obtain a current density of 10 mA/cm(2) (requirement for >10% efficient devices) at 1.15 V versus RHE (reversible hydrogen electrode) under red-light (38.6 mW/cm(2)) irradiation. Thus, the photoanodes were harvesting ∼80 mV of free energy (voltage), which places them among the best-performing Si-based photoanodes in alkaline media. The stability was proven by chronoamperometry at 1.3 V versus RHE for 300 h. Furthermore, measurements with electrochemical quartz crystal microbalances coupled with ICP-MS showed minor corrosion under dark operation. Extrapolation of the corrosion rate showed stability for more than 2000 days of continuous operation. Therefore, protection by Fe-treated NiO films is a promising strategy to achieve highly efficient and stable photoanodes.
†Department of Physics, Center for Individual Nanoparticle Functionality (CINF) and ‡Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Bastian
B
Mei
†Department of Physics, Center for Individual Nanoparticle Functionality (CINF) and ‡Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Anastasia A
AA
Permyakova
†Department of Physics, Center for Individual Nanoparticle Functionality (CINF) and ‡Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Rasmus
R
Frydendal
†Department of Physics, Center for Individual Nanoparticle Functionality (CINF) and ‡Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Dowon
D
Bae
†Department of Physics, Center for Individual Nanoparticle Functionality (CINF) and ‡Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Thomas
T
Pedersen
†Department of Physics, Center for Individual Nanoparticle Functionality (CINF) and ‡Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Paolo
P
Malacrida
†Department of Physics, Center for Individual Nanoparticle Functionality (CINF) and ‡Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Ole
O
Hansen
†Department of Physics, Center for Individual Nanoparticle Functionality (CINF) and ‡Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Ifan E L
IE
Stephens
†Department of Physics, Center for Individual Nanoparticle Functionality (CINF) and ‡Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Peter C K
PC
Vesborg
†Department of Physics, Center for Individual Nanoparticle Functionality (CINF) and ‡Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Brian
B
Seger
†Department of Physics, Center for Individual Nanoparticle Functionality (CINF) and ‡Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
Ib
I
Chorkendorff
electrochemical quartz crystal microbalance; oxygen evolution reaction (OER); photoelectrochemical water splitting; stability; thin film