Abstract
The behavior of n-Si(111) photoanodes covered by monolayer sheets of fluorinated graphene (F-Gr) was investigated under a range of chemical and electrochemical conditions. The electrochemical behavior of n-Si/F-Gr and np+-Si/F-Gr photoanodes was compared to hydride-terminated n-Si (n-Si-H) and np+-Si-H electrodes in contact with aqueous Fe(CN)6 3-/4- and Br2/HBr electrolytes as well as in contact with a series of outer-sphere, one-electron redox couples in nonaqueous electrolytes. Illuminated n-Si/F-Gr and np+-Si/F-Gr electrodes in contact with an aqueous K3(Fe(CN)6/K4(Fe(CN)6 solutions exhibited stable short-circuit photocurrent densities of ∼10 mA cm-2 for 100,000 s (>24 h), in comparison to bare Si electrodes, which yielded nearly a complete photocurrent decay over ∼100 s. X-ray photoelectron spectra collected before and after exposure to aqueous anodic conditions showed that oxide formation at the Si surface was significantly inhibited for Si electrodes coated with F-Gr relative to bare Si electrodes exposed to the same conditions. The variation of the open-circuit potential for n-Si/F-Gr in contact with a series of nonaqueous electrolytes of varying reduction potential indicated that the n-Si/F-Gr did not form a buried junction with respect to the solution contact. Further, illuminated n-Si/F-Gr electrodes in contact with Br2/HBr(aq) were significantly more electrochemically stable than n-Si-H electrodes, and n-Si/F-Gr electrodes coupled to a Pt catalyst exhibited ideal regenerative cell efficiencies of up to 5% for the oxidation of Br- to Br2.
| Original language | English |
|---|---|
| Pages (from-to) | 4082-4086 |
| Number of pages | 5 |
| Journal | Nano Letters |
| Volume | 16 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - Jul 13 2016 |
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Keywords
- 2D materials
- anticorrosion
- graphene
- Photoelectrochemistry
- solar energy conversion
ASJC Scopus subject areas
- Condensed Matter Physics
- Bioengineering
- Chemistry(all)
- Materials Science(all)
- Mechanical Engineering
Cite this
Lightly Fluorinated Graphene as a Protective Layer for n-Type Si(111) Photoanodes in Aqueous Electrolytes. / Nielander, Adam C.; Thompson, Annelise C.; Roske, Christopher W.; Maslyn, Jacqueline A.; Hao, Yufeng; Plymale, Noah T.; Hone, James; Lewis, Nathan S.
In: Nano Letters, Vol. 16, No. 7, 13.07.2016, p. 4082-4086.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Lightly Fluorinated Graphene as a Protective Layer for n-Type Si(111) Photoanodes in Aqueous Electrolytes
AU - Nielander, Adam C.
AU - Thompson, Annelise C.
AU - Roske, Christopher W.
AU - Maslyn, Jacqueline A.
AU - Hao, Yufeng
AU - Plymale, Noah T.
AU - Hone, James
AU - Lewis, Nathan S
PY - 2016/7/13
Y1 - 2016/7/13
N2 - The behavior of n-Si(111) photoanodes covered by monolayer sheets of fluorinated graphene (F-Gr) was investigated under a range of chemical and electrochemical conditions. The electrochemical behavior of n-Si/F-Gr and np+-Si/F-Gr photoanodes was compared to hydride-terminated n-Si (n-Si-H) and np+-Si-H electrodes in contact with aqueous Fe(CN)6 3-/4- and Br2/HBr electrolytes as well as in contact with a series of outer-sphere, one-electron redox couples in nonaqueous electrolytes. Illuminated n-Si/F-Gr and np+-Si/F-Gr electrodes in contact with an aqueous K3(Fe(CN)6/K4(Fe(CN)6 solutions exhibited stable short-circuit photocurrent densities of ∼10 mA cm-2 for 100,000 s (>24 h), in comparison to bare Si electrodes, which yielded nearly a complete photocurrent decay over ∼100 s. X-ray photoelectron spectra collected before and after exposure to aqueous anodic conditions showed that oxide formation at the Si surface was significantly inhibited for Si electrodes coated with F-Gr relative to bare Si electrodes exposed to the same conditions. The variation of the open-circuit potential for n-Si/F-Gr in contact with a series of nonaqueous electrolytes of varying reduction potential indicated that the n-Si/F-Gr did not form a buried junction with respect to the solution contact. Further, illuminated n-Si/F-Gr electrodes in contact with Br2/HBr(aq) were significantly more electrochemically stable than n-Si-H electrodes, and n-Si/F-Gr electrodes coupled to a Pt catalyst exhibited ideal regenerative cell efficiencies of up to 5% for the oxidation of Br- to Br2.
AB - The behavior of n-Si(111) photoanodes covered by monolayer sheets of fluorinated graphene (F-Gr) was investigated under a range of chemical and electrochemical conditions. The electrochemical behavior of n-Si/F-Gr and np+-Si/F-Gr photoanodes was compared to hydride-terminated n-Si (n-Si-H) and np+-Si-H electrodes in contact with aqueous Fe(CN)6 3-/4- and Br2/HBr electrolytes as well as in contact with a series of outer-sphere, one-electron redox couples in nonaqueous electrolytes. Illuminated n-Si/F-Gr and np+-Si/F-Gr electrodes in contact with an aqueous K3(Fe(CN)6/K4(Fe(CN)6 solutions exhibited stable short-circuit photocurrent densities of ∼10 mA cm-2 for 100,000 s (>24 h), in comparison to bare Si electrodes, which yielded nearly a complete photocurrent decay over ∼100 s. X-ray photoelectron spectra collected before and after exposure to aqueous anodic conditions showed that oxide formation at the Si surface was significantly inhibited for Si electrodes coated with F-Gr relative to bare Si electrodes exposed to the same conditions. The variation of the open-circuit potential for n-Si/F-Gr in contact with a series of nonaqueous electrolytes of varying reduction potential indicated that the n-Si/F-Gr did not form a buried junction with respect to the solution contact. Further, illuminated n-Si/F-Gr electrodes in contact with Br2/HBr(aq) were significantly more electrochemically stable than n-Si-H electrodes, and n-Si/F-Gr electrodes coupled to a Pt catalyst exhibited ideal regenerative cell efficiencies of up to 5% for the oxidation of Br- to Br2.
KW - 2D materials
KW - anticorrosion
KW - graphene
KW - Photoelectrochemistry
KW - solar energy conversion
UR - http://www.scopus.com/inward/record.url?scp=84978776293&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84978776293&partnerID=8YFLogxK
U2 - 10.1021/acs.nanolett.6b00773
DO - 10.1021/acs.nanolett.6b00773
M3 - Article
VL - 16
SP - 4082
EP - 4086
JO - Nano Letters
JF - Nano Letters
SN - 1530-6984
IS - 7
ER -