Towards a perfect system for solar hydrogen production: an example of synergy on the atomic scale

Nashed, Ramy; Alamgir, Faisal M.; Jang, Seung-Soon; Ismail, Yehea; El‐Sayed, Mostafa A.; Allam, Nageh K.

doi:10.1117/12.2026337

Cited by 1 publication

(2 citation statements)

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“…Electrons have a potential barrier toward the Ta 2 O 5 side, which forces them to flow rightward, whereas holes have a potential barrier toward the WO 3 side forcing them to flow leftward, and hence an efficient charge separation is achieved . On the other hand, straddled band alignment (such as that present in Ti–Fe–O system) gives rise to electron trapping in the conduction band, as shown in Figure b, and, in turn, reduces the conversion efficiency. , We believe that this is the main reason behind the modest efficiency reported so far for photoelectrochemical water splitting systems based on straddled band alignment.…”

Section: Resultssupporting

confidence: 84%

“…9 On the other hand, straddled band alignment (such as that present in TiÀFeÀO system) gives rise to electron trapping in the conduction band, as shown in Figure 3b, and, in turn, reduces the conversion efficiency. 9,12 We believe that this is the main reason behind the modest efficiency reported so far for photoelectrochemical water splitting systems based on straddled band alignment.…”

Section: Figure S1 (Supporting Information)mentioning

confidence: 99%

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Self-Assembled Nanostructured Photoanodes with Staggered Bandgap for Efficient Solar Energy Conversion

et al. 2014

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Vertically oriented Ta-W-O nanotube array films were fabricated via the anodization of Ta-W alloy foils in HF-containing electrolytes. HF concentration is a key parameter in achieving well-adhered nanotube array structure. X-ray photoelectron spectroscopy (XPS) and diffuse reflectance measurements confirm the staggered band-alignment between Ta2O5 and WO3, which facilitates the separation of charge carriers. The nanotubes made of Ta-W films containing 10% W showed 100-fold improvement in the measured photocurrent compared to pristine Ta2O5 upon their use to split water photoelectrochemically. This enhancement was related to the efficient charge transport and the red shift in absorption spectrum with increase of the W content, which was asserted by ultrafast transient absorption (TA) spectroscopy measurements. The TA measurements showed the elimination of trap states upon annealing Ta-W-O nanotubes and, hence, minimizing the charge carrier trapping, whereas the trap states remain in pristine Ta2O5 nanotubes even after annealing.

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Section: Resultssupporting

confidence: 84%