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Photoelectrochemical water splitting employing a tapered silicon nanohole array

Title
Photoelectrochemical water splitting employing a tapered silicon nanohole array
Author
방진호
Keywords
SOLAR-CELLS; POROUS SILICON; SURFACE PASSIVATION; HYDROGEN-PRODUCTION; NANOWIRE ARRAYS; PERFORMANCE; ENERGY; RECOMBINATION; OPTIMIZATION; PHOTOCATHODE
Issue Date
2014-01
Publisher
ROYAL SOC CHEMISTRY
Citation
JOURNAL OF MATERIALS CHEMISTRY A, 2(3) ,Pages 833-842
Abstract
An effective photocathode adopting a tapered Si nanohole (SiNH) array has been developed for photoelectrochemical water splitting. The tapered feature of SiNH photocathodes resulted in a gradation of the refractive indices between Si and air, such that the mismatching of optical impedance was alleviated and light absorption was enhanced. Adjusting the depth of the SiNHs successfully simulated the number of dielectric layers, optimizing the destructive interference for an antireflective coating (ARC). Only a 200 nm-thin NH array was required to absorb similar to 96% of solar spectral irradiance for photoelectrochemical applications. This thickness also minimized the undesirable surface recombination loss. When compared to a similar system using a planar technology, the formation of NHs was observed to cause an increase in the optical bandgap. This could generate a surface-passivation effect, resulting in a lowering of dark current and an increase in photovoltage, which could be utilized for an anodic shift of the onset voltage. Due to the addition of tapered SiNHs, the photogenerated current was improved by similar to 30% (similar to 33 mA cm(-2)) compared to a planar counterpart (similar to 25 mA cm(-2)), while the overpotential required for H-2 evolution was reduced.
URI
http://pubs.rsc.org/en/content/articlelanding/2014/ta/c3ta14439a#!divAbstracthttp://hdl.handle.net/20.500.11754/53800
ISSN
2050-7488; 2050-7496
DOI
10.1039/c3ta14439a
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GRADUATE SCHOOL[S](대학원) > ETC
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