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CdSSe layer-sensitized TiO2 nanowire arrays as efficient photoelectrodes

2011; Royal Society of Chemistry; Volume: 21; Issue: 12 Linguagem: Inglês

10.1039/c0jm03818k

1364-5501

Tae Kwang Sung, Jun Ha Kang, Dong Myung Jang, Yoon Myung, Gyeong Bok Jung, Han Sung Kim, Chan Su Jung, Yong Jae Cho, Jeunghee Park, Chang‐Lyoul Lee,

Chalcogenide Semiconductor Thin Films

Complete composition-tuned CdSxSe1−x alloy layers (avg. thickness = 50 nm) were deposited on pre-grown TiO2 nanowires by the thermal vapor transport of CdS/CdSe powders, producing core–shell nanocable arrays. CdSxSe1−x alloy nanowires were also synthesized with full composition tuning by the same method for comparison. The CdSSe nanowires consisted of Se-rich and S-rich pseudo binary phases, while the nanocable shell consisted of more complex multinary phases including CdSe and CdS. Remarkably, unique CdS–CdSSe–CdSe multishell structures were produced in the Se-rich composition range. The photoelectrochemical (PEC) cells fabricated using the as-grown nanocable arrays show higher solar photocurrents and hydrogen generation rates for the Se-rich shelled TiO2 nanocable arrays. This suggests that the CdS–CdSSe–CdSe multishell structures increase greatly the PEC performance by producing novel band alignment for efficient electron–hole separation following enhanced visible-range photon absorption.