Solution-processed multilayered BiVO₄ photoanodes: influence of intermediate heat treatments on the photoactivity

Abstract

Intermediate heat treatments to at least 350 °C are needed to obtain fully crystalline monoclinic BiVO4 films with tunable thickness from spin coating of successive layers from a precursor solution.

Recent Advances in Bismuth‐Based Nanomaterials for Photoelectrochemical Water Splitting

“…[71,72] The theoretical solar-to-hydrogen conversion efficiency of BiVO 4 reaches up to 9.2 %w ith am aximum photocurrent of 7.5 mA cm À2 . [80] They also report that final annealing in the presence of water vapor and oxygen improves the connectivity of the grains and, thus, increasesthe photocurrent. The conduction band is positioned below the hydrogen reduction potential, and hence, it cannot evolve hydrogen from water.…”

“…[36,[70][71][72] Recent reportsi ndicate that BiVO 4 possesses an indirectb and gap. [80] Preheating of individual spin-coated BiVO 4 layers at ah igh temperature (above 400 8C) increases the charge-transport properties;h owever,i t reduces injection efficiency into the electrolyte. [73][74][75] BiVO 4 suffers from af ew limitations, including slow electron-hole pair migration and sluggish oxygen-evolution kinetics.…”

“…[73][74][75] BiVO 4 suffers from af ew limitations, including slow electron-hole pair migration and sluggish oxygen-evolution kinetics. [80] Kuang et al demonstrated the enhanced front-illumination performance of BiVO 4 along with enhanced charge-separation efficiency and light transmittancy. The conduction band minimac onsist of the Bi 6p, V3d, and O2ps tates, whereas the valenceb and maxima comprise the Bi 6s and O2ss tates.W alsh et al have provided the detailed electronic structure of BiVO 4 .…”

“…[ 79] Chemseddine et al present the importance of intermediate heatingofBiVO 4 films on PEC performance. [80] Preheating of individual spin-coated BiVO 4 layers at ah igh temperature (above 400 8C) increases the charge-transport properties;h owever,i t reduces injection efficiency into the electrolyte. [80] They also report that final annealing in the presence of water vapor and oxygen improves the connectivity of the grains and, thus, increasesthe photocurrent.…”

“…[80] Preheating of individual spin-coated BiVO 4 layers at ah igh temperature (above 400 8C) increases the charge-transport properties;h owever,i t reduces injection efficiency into the electrolyte. [80] They also report that final annealing in the presence of water vapor and oxygen improves the connectivity of the grains and, thus, increasesthe photocurrent. [80] Kuang et al demonstrated the enhanced front-illumination performance of BiVO 4 along with enhanced charge-separation efficiency and light transmittancy.…”