Elucidating the Sole Contribution from Electromagnetic Near-Fields in Plasmon-Enhanced Cu2O Photocathodes

Autor: Benjamin P. Williams, Mathieu Gomes, Aaron C. Johnston-Peck, Wei David Wei, Dong Su, Maxime Amilhau, Fengwei Huo, Jingjing Qiu, Eric A. Stach, Joseph S. DuChene, Donald Bejleri, Jiena Weng
Rok vydání: 2015
Předmět:
Zdroj: Advanced Energy Materials. 6:1501250
ISSN: 1614-6832
DOI: 10.1002/aenm.201501250
Popis: Despite many promising reports of plasmon-enhanced photocatalysis, the inability to identify the individual contributions from multiple enhancement mechanisms has delayed the development of general design rules for engineering efficient plasmonic photocatalysts. Herein, a plasmonic photocathode comprised of Au@SiO2 (core@shell) nanoparticles embedded within a Cu2O nanowire network is constructed to exclusively examine the contribution from one such mechanism: electromagnetic near-field enhancement. The influence of the local electromagnetic field intensity is correlated with the overall light-harvesting efficiency of the device through variation of the SiO2 shell thickness (5–22 nm) to systematically tailor the distance between the plasmonic Au nanoparticles and the Cu2O nanowires. A threefold increase in device photocurrent is achieved upon integrating the Au@SiO2 nanoparticles into the Cu2O nanowire network, further enabling a 40% reduction in semiconductor film thickness while maintaining photocathode performance. Photoelectrochemical results are further correlated with photoluminescence studies and optical simulations to confirm that the near-field enhancement is the sole mechanism responsible for increased light absorption in the plasmonic photocathode.
Databáze: OpenAIRE
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