Enhanced charge collection and surface activity of a CuBi₂O₄ photocathode via crystal facet engineering

Abstract

Transition metal oxide semiconductors are important candidates for photoelectrodes to convert solar energy to fuels. However, the practical applications of these materials are hindered by severe carrier losses and sluggish...

Generation of Stable Photovoltage in Nonstoichiometric CuBi2O4 Thin-Film Photocathodes

“…These results reveal that stoichiometry manipulation affects PEC properties of the CBO photocathodes. Accordingly, it is imperative to understand the relationship between stoichiometry and PEC properties to overcome catalytic degradation such as photocorrosion, originating from the sluggish surfaceexchange kinetics in CBO photocathodes [25].…”

Optoelectrical Regulation of CuBi2O4 Photocathode via Photonic Crystal Structure for Solar–Fuel Conversion

“…Because of its small polaron hopping conduction mechanism, CBO shows a low carrier mobility (∼1.2 × 10 –3 cm 2 V –1 s –1 ) and a short minority carrier diffusion length around 45 nm, , significantly shorter than its photon absorption depth (α 400 –1 = 200 nm). Thus, most photocarriers are lost inside the bulk through recombination rather than reaching the interface and participating in the PEC reaction . Therefore, a feasible approach is still demanded to balance the photon absorption and carrier collection so that the performance of photoelectrodes can be boosted.…”

“…Thus, most photocarriers are lost inside the bulk through recombination rather than reaching the interface and participating in the PEC reaction. 12 Therefore, a feasible approach is still demanded to balance the photon absorption and carrier collection so that the performance of photoelectrodes can be boosted.…”

Full-Space Potential Gradient Driven Charge Migration inside BiFeO3 Photocathode

“…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. 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.…”

“…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.…”