High-Performance <i>a</i>‑Si/c-Si
Heterojunction Photoelectrodes for Photoelectrochemical Oxygen and
Hydrogen Evolution
- Publication date
- Publisher
Abstract
Amorphous Si (<i>a</i>-Si)/crystalline
Si (c-Si) heterojunction (SiHJ) can serve as highly efficient and
robust photoelectrodes for solar fuel generation. Low carrier recombination
in the photoelectrodes leads to high photocurrents and photovoltages.
The SiHJ was designed and fabricated into both photoanode and photocathode
with high oxygen and hydrogen evolution efficiency, respectively,
by simply coating of a thin layer of catalytic materials. The SiHJ
photoanode with sol–gel NiO<sub><i>x</i></sub> as
the catalyst shows a current density of 21.48 mA/cm<sup>2</sup> at
the equilibrium water oxidation potential. The SiHJ photocathode with
2 nm sputter-coated Pt catalyst displays excellent hydrogen evolution
performance with an onset potential of 0.640 V and a solar to hydrogen
conversion efficiency of 13.26%, which is the highest ever reported
for Si-based photocathodes