BiFeO₃ photocathodes for efficient H₂O₂ production via charge carrier dynamics engineering

Abstract

Metal oxide semiconductors are promising candidate photoelectrodes for photoelectrochemical H2O2 production if the issue of poor efficiency and selectivity can be resolved. An unfavorable charge transport barrier causes poor carrier...

Full-Space Potential Gradient Driven Charge Migration inside BiFeO3 Photocathode

“…Constructing an internal electric field in the natural region as an additional driving force is critical to promote photocarriers collection. 12 So far, various strategies have been widely employed to build an electric field, such as surface tailoring, 13 heterojunction, 14,15 and facet junction. 16,17 However, the influence of these electric fields is mostly spatially limited to the surface or depletion area, rarely modulating the recombination process in the field-free region.…”

“…16,17 However, the influence of these electric fields is mostly spatially limited to the surface or depletion area, rarely modulating the recombination process in the field-free region. 15,18,19 The depolarization field is a typical way to promote charge separation in both bulk and surface, while it is confined to ferroelectrics. 20,21 Thus, a universal approach to construct fullspace electric field through the photoelectrode is the remedial approach to inhibit carrier recombination.…”

“…These peaks are attributed to the ligand-to-metal charge transition between O-to-Bi (2.27 eV) and O-to-Fe (1.82 eV). 15 Figure 5g and Figure S8b are the transmission spectra extracted from the contour maps of BFO films in the visible region at different delay times. The ratio changes in BFO films rarely influence the sharpness of spectra.…”

“…Constructing an internal electric field in the natural region as an additional driving force is critical to promote photocarriers collection . So far, various strategies have been widely employed to build an electric field, such as surface tailoring, heterojunction, , and facet junction. , However, the influence of these electric fields is mostly spatially limited to the surface or depletion area, rarely modulating the recombination process in the field-free region. ,, The depolarization field is a typical way to promote charge separation in both bulk and surface, while it is confined to ferroelectrics. , Thus, a universal approach to construct full-space electric field through the photoelectrode is the remedial approach to inhibit carrier recombination.…”

“…Figure f and Figure S8a show the transmission contour maps of BFO film that contain two main peaks located at 460 nm (2.65 eV) and 520 nm (2.38 eV) which decrease over time. These peaks are attributed to the ligand-to-metal charge transition between O-to-Bi (2.27 eV) and O-to-Fe (1.82 eV) Figure g and Figure S8b are the transmission spectra extracted from the contour maps of BFO films in the visible region at different delay times.…”