Electrical and Photoelectrochemical Properties of WO3/Si Tandem Photoelectrodes

Tungsten trioxide (WO3) has been investigated as a photoanode for water oxidation reactions in acidic aqueous conditions. Though WO3 is not capable of performing unassisted solar-driven water splitting, WO3 can in principle be coupled with a low band gap semiconductor, such as Si, to produce a stand-alone, tandem photocathode/photoanode p-Si/n-WO3 system for solar fuels production. Junctions between Si and WO3, with and without intervening ohmic contacts, were therefore prepared and investigated in detail. Thin films of n-WO3 that were prepared directly on p-Si and n-Si substrates exhibited an onset of photocurrent at a potential consistent with expectations based on the band-edge alignment of these two materials predicted by Andersen theory. However, n-WO3 films deposited on Si substrates exhibited much lower anodic photocurrent densities (∼0.02 mA cm–2 at 1.0 V vs SCE) than identically prepared n-WO3 films that were deposited on fluorine-doped tin oxide (FTO) substrates (0.45 mA cm–2 at 1.0 V vs SCE). D...

[1]  S. Tanisaki.  Crystal Structure of Monoclinic Tungsten Trioxide at Room Temperature , 1960 .

[2]  Volker Lehmann,et al.  Electrochemistry of Silicon , 2002 .

[3]  E. Meulenkamp.  Mechanism of WO3 electrodeposition from peroxy-tungstate solution , 1997 .

[4]  Turner,et al.  A monolithic photovoltaic-photoelectrochemical device for hydrogen production via water splitting , 1998, Science.

[5]  W. Ahlgren.  Analysis of the Current‐Voltage Characteristics of Photoelectrolysis Cells , 1981 .

[6]  N. Lewis,et al.  Improvement of photoelectrochemical hydrogen generation by surface modification of p-type silicon semiconductor photocathodes , 1982 .

[7]  M. P. D. Santos,et al.  Properties of indium tin oxide (ITO) films prepared by r.f. reactive magnetron sputtering at different pressures , 1997 .

[8]  R. Rocheleau,et al.  Optimization of Hybrid Photoelectrodes for Solar Water-Splitting , 2005 .

[9]  Jan Augustynski,et al.  Photoelectrochemical Properties of Nanostructured Tungsten Trioxide Films , 2001 .

[10]  Yong Xu,et al.  The absolute energy positions of conduction and valence bands of selected semiconducting minerals , 2000 .

[11]  R.L. Anderson.  Experiments on Ge-GaAs heterojunctions , 1962, IRE Transactions on Electron Devices.

[12]  P. Kulesza,et al.  Metal oxide photoanodes for solar hydrogen production , 2008 .

[13]  Alfonso Franciosi,et al.  Heterojunction band offset engineering , 1996 .

[14]  Lin-wang Wang,et al.  Si:WO3 heterostructure for Z-scheme water splitting: an ab initio study , 2013 .

[15]  Choul Woo Shin,et al.  Photoelectrochemical conversion in a WO3 coated p-Si photoelectrode: Effect of annealing temperature , 1997 .

[16]  Eric L. Miller,et al.  Development of reactively sputtered metal oxide films for hydrogen-producing hybrid multijunction photoelectrodes , 2005 .

[17]  S. Ashok,et al.  On resolving the anomaly of indium-tin oxide silicon junctions , 1981, IEEE Electron Device Letters.

[18]  Yun Jeong Hwang,et al.  High density n-Si/n-TiO2 core/shell nanowire arrays with enhanced photoactivity. , 2009, Nano letters.

[19]  W. Gissler,et al.  Photoelectrochemical Processes at Semiconducting WO 3 Layers , 1977 .

[20]  M. Grätzel.  Photoelectrochemical cells : Materials for clean energy , 2001 .

[21]  Dunwei Wang,et al.  Hematite/Si nanowire dual-absorber system for photoelectrochemical water splitting at low applied potentials. , 2012, Journal of the American Chemical Society.