Enhanced photocathodic behaviors of Pb(Zr_(0.20)Ti_(0.80))O_3 films on Si substrates for hydrogen production

摘要

Wide bandgap ferroelectric Pb(Zr_(0.20)Ti_(0.80))O_3 films were deposited on indium tin oxide (ITO) coated Si-pn~+ substrates with an intention to form efficient Si-pn~+/ITO/Pb(Zr,Ti)O_3 (PZT) photocathode for hydrogen production. Depolarization electric field generated in PZT film due to poling can drive the photogenerated electrons from Si-pn~+ junction to PZT film, resulting in enhanced photoelectrochemical activity of the photocathode. Comparing the electrode with as-prepared PZT film, the photocurrent increased from -100 μA cm~(-2) to -1.2 mA cm~(-2) at 0 V vs. reversible hydrogen electrode (RHE) and the onset potential from 0.36 V to 0.7 V vs. RHE under 100 mW cm~(-2) illumination, manifesting the great advantage of depolarization electric field in driving the photogenerated carriers not only in the ferroelectric film but also on the interface of different semiconductors.