Abstract
Arrays of Si microwires doped n-type (n-Si) and surface-functionalized with methyl groups have been used, with or without deposition of Pt electrocatalysts, to photoelectrochemically oxidize I-(aq) to I3 -(aq) in 7.6 M HI(aq). Under conditions of iodide oxidation, methyl-terminated n-Si microwire arrays exhibited stable short-circuit photocurrents over a time scale of days, albeit with low energy-conversion efficiencies. In contrast, electrochemical deposition of Pt onto methyl-terminated n-Si microwire arrays consistently yielded energy-conversion efficiencies of ∼2% for iodide oxidation, with an open-circuit photovoltage of ∼400 mV and a short-circuit photocurrent density of ∼10 mA cm-2 under 100 mW cm-2 of simulated air mass 1.5G solar illumination. Platinized electrodes were stable for >200 h of continuous operation, with no discernible loss of Si or Pt. Pt deposited using electron-beam evaporation also resulted in stable photoanodic operation of the methyl-terminated n-Si microwire arrays but yielded substantially lower photovoltages than when Pt was deposited electrochemically.
| Original language | English |
|---|---|
| Pages (from-to) | 2308-2314 |
| Number of pages | 7 |
| Journal | ACS Energy Letters |
| Volume | 4 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - Sep 13 2019 |
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ASJC Scopus subject areas
- Chemistry (miscellaneous)
- Renewable Energy, Sustainability and the Environment
- Fuel Technology
- Energy Engineering and Power Technology
- Materials Chemistry
Cite this
Enhanced Stability and Efficiency for Photoelectrochemical Iodide Oxidation by Methyl Termination and Electrochemical Pt Deposition on n-Type Si Microwire Arrays. / Ardo, Shane; Santori, Elizabeth A.; Emmer, Hal S.; Grimm, Ronald L.; Bierman, Matthew J.; Brunschwig, Bruce S.; Atwater, Harry A.; Lewis, Nathan S.
In: ACS Energy Letters, Vol. 4, No. 9, 13.09.2019, p. 2308-2314.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Enhanced Stability and Efficiency for Photoelectrochemical Iodide Oxidation by Methyl Termination and Electrochemical Pt Deposition on n-Type Si Microwire Arrays
AU - Ardo, Shane
AU - Santori, Elizabeth A.
AU - Emmer, Hal S.
AU - Grimm, Ronald L.
AU - Bierman, Matthew J.
AU - Brunschwig, Bruce S.
AU - Atwater, Harry A.
AU - Lewis, Nathan S.
PY - 2019/9/13
Y1 - 2019/9/13
N2 - Arrays of Si microwires doped n-type (n-Si) and surface-functionalized with methyl groups have been used, with or without deposition of Pt electrocatalysts, to photoelectrochemically oxidize I-(aq) to I3 -(aq) in 7.6 M HI(aq). Under conditions of iodide oxidation, methyl-terminated n-Si microwire arrays exhibited stable short-circuit photocurrents over a time scale of days, albeit with low energy-conversion efficiencies. In contrast, electrochemical deposition of Pt onto methyl-terminated n-Si microwire arrays consistently yielded energy-conversion efficiencies of ∼2% for iodide oxidation, with an open-circuit photovoltage of ∼400 mV and a short-circuit photocurrent density of ∼10 mA cm-2 under 100 mW cm-2 of simulated air mass 1.5G solar illumination. Platinized electrodes were stable for >200 h of continuous operation, with no discernible loss of Si or Pt. Pt deposited using electron-beam evaporation also resulted in stable photoanodic operation of the methyl-terminated n-Si microwire arrays but yielded substantially lower photovoltages than when Pt was deposited electrochemically.
AB - Arrays of Si microwires doped n-type (n-Si) and surface-functionalized with methyl groups have been used, with or without deposition of Pt electrocatalysts, to photoelectrochemically oxidize I-(aq) to I3 -(aq) in 7.6 M HI(aq). Under conditions of iodide oxidation, methyl-terminated n-Si microwire arrays exhibited stable short-circuit photocurrents over a time scale of days, albeit with low energy-conversion efficiencies. In contrast, electrochemical deposition of Pt onto methyl-terminated n-Si microwire arrays consistently yielded energy-conversion efficiencies of ∼2% for iodide oxidation, with an open-circuit photovoltage of ∼400 mV and a short-circuit photocurrent density of ∼10 mA cm-2 under 100 mW cm-2 of simulated air mass 1.5G solar illumination. Platinized electrodes were stable for >200 h of continuous operation, with no discernible loss of Si or Pt. Pt deposited using electron-beam evaporation also resulted in stable photoanodic operation of the methyl-terminated n-Si microwire arrays but yielded substantially lower photovoltages than when Pt was deposited electrochemically.
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U2 - 10.1021/acsenergylett.9b01529
DO - 10.1021/acsenergylett.9b01529
M3 - Article
AN - SCOPUS:85072632526
VL - 4
SP - 2308
EP - 2314
JO - ACS Energy Letters
JF - ACS Energy Letters
SN - 2380-8195
IS - 9
ER -