Development of a hybrid photoelectrochemical (PEC) device with amorphous silicon carbide as the photoelectrode for water
- PDF / 499,061 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 49 Downloads / 228 Views
1171-S03-05
Development of a hybrid photoelectrochemical (PEC) device with amorphous silicon carbide as the photoelectrode for water splitting Jian Hu1, Feng Zhu1, Ilvydas Matulionis1, Todd Deutsch2, Nicolas Gaillard3, Eric Miller3, and Arun Madan1 1
，
MVSystems, Inc., 500 Corporate Circle, Suite L, Golden, CO, 80401 USA National Renewable Energy Laboratory (NREL), Golden, CO 80401, USA 3 Hawaii Natural Energy Institute (HNEI), University of Hawaii at Manoa, Honolulu, HI 96822, USA 2
ABSTRACT We report on an integrated photoelectrochemical (PEC) device for hydrogen production using amorphous silicon carbide (a-SiC:H) material as the photoelectrode in conjunction with an amorphous silicon (a-Si:H) tandem photovoltaic device. With the use of a-Si:H tandem solar cell, the flat-band potential of the hybrid PEC structure shifts significantly below the H2O/O2 halfreaction potential and is in an appropriate position to facilitate water splitting. Under reverse bias, saturated photocurrent of the hybrid device ranges between 3 to 5 mA/cm2 under AM1.5 light intensity. In a two-electrode setup (with ruthenium oxide counter electrode), which is analogous to a real PEC configuration, the hybrid cell produces photocurrent of about 0.83 mA/cm2 at zero bias and hydrogen production is observed. The hybrid device exhibits good durability in pH2 buffered electrolyte for up to 150 hours (so far tested). INTRODUCTION Hydrogen is emerging as an alternative energy carrier to fossil fuels due to its non-toxic and environmentally friendly nature. Compared with other conventional methods (e.g., direct electrolysis, thermo-chemical decomposition of water and so on), photoelectrochemical (PEC) water splitting at a semiconductor-electrolyte interface using sunlight is of considerable interest as it offers an environmentally “green” approach to hydrogen production [1.2]. An efficient PEC water splitting device requires the semiconductor material used as a photoelectrode fulfilling a number of primary requirements, such as bandgap (Eg), band edge alignment and corrosion resistance to electrolyte. We have previously reported on a PEC device with amorphous silicon tandem junction with a WO3 photoanode, leading to a 3% solar-to-hydrogen (STH) efficiency [3]; we have also reported a similar PEC device with the hydrogenated amorphous silicon carbide (a-SiC:H) photoelectrode fabricated by the plasma enhanced chemical vapor deposition (PECVD) technique [4,5]. Compared with conventional large bandgap photoelectrode materials (e.g., WO3 with Eg of ~2.8eV), a-SiC:H film with a lower Eg (2.0-2.3 eV) would absorb more photons from sunlight and thus should enhance the STH efficiency. It should be noted that incorporation of the C in the film should lead to an increase in the corrosion resistance compared to the use of conventional a-Si:H films, which have poor stability in the electrolyte [6]. Moreover, a-SiC:H films are routinely prepared by the PECVD technique which is normally used in the fabrication of a-Si tandem solar cells. This could become very
Data Loading...
