Charge carrier transport dynamics in W/Mo-doped BiVO₄: first principles-based mesoscale characterization

Abstract

First principles-based mesoscale characterization of electron transport in W/Mo-doped BiVO4 reveals the existence of “stabilization” regions around dopant sites. The stabilization regions decrease slightly the electron polaron mobility, albeit the overall electrode conductivity increases.

Freeing the Polarons to Facilitate Charge Transport in BiVO4 from Oxygen Vacancies with an Oxidative 2D Precursor

“…However,t here still remains the key issue that carrier transport inside the BiVO 4 photoelectrode is too sluggish, making the water splitting performance quite low when light was illuminated from the ESI side. [18][19][20][21][22] Our previous work unveiled that the poor performance is mainly due to the slow,t rap-limited electron transport by investigating the performance difference between the light illumination from the ESI side and from the FTO side. [22] Recent advances disclosed that the poor majority carrier transport of BiVO 4 is caused by the formation of electron small polarons.…”

“…[15,27,28] To tackle the slow carrier transport issue,d opants were introduced, such as molybdenum and hydrogen. [16,18,20,29] Conceivably,amore direct and effective way to get to the root of the issue is to control the oxygen vacancy itself and, in doing so,toengineer the polaron hopping dynamics,b ut no effective method has been developed as yet.…”

Multi‐Metal Nanocluster Assisted Cu‐Ga‐Sn Tri‐Doping for Enhanced Photoelectrochemical Water Splitting of BiVO4 Film

“…[ 23 ] Li's group suggested that W/Mo doping increased the carrier concentration and the conductivity of BiVO 4 by a density functional theory DFT + U method. [ 24 ] Nevertheless, multi‐element doping is difficult to be implemented in most cases because the operation steps are cumbersome, and normally requires expensive equipment such as ion implanter. [ 25,26 ] The even distribution and avoidance of phase separation during calcination also remain challenging when the mixture of precursors are used.…”

Rational Design of 3D Hierarchical Ternary SnO2/TiO2/BiVO4 Arrays Photoanode toward Efficient Photoelectrochemical Performance

“…Nevertheless, the poor charge transport ability, short carrier diffusion lengths (≈70 nm), and high charge recombination rates of BiVO 4 greatly limit its practical PEC performance. To address these problems, various strategies such as morphology design, element doping, host–guest heterojunctions and surface modifications are developed to enhance the performance . Nanostructured electrode design is one effective route to enhance the light absorption and charge transport ability.…”

“…In the past decades, metal oxides such as TiO 2 , [5,6] Fe 2 O 3 , [7][8][9] and BiVO 4 [10][11][12] have been widely investigated as photoanodes for PEC water splitting due to the characteristics of excellent photoactivity, low cost, and good stability. [19][20][21][22][23][24] Nanostructured electrode design is one effective route to enhance the light absorption and charge transport ability. [13][14][15][16][17][18] Nevertheless, the poor charge transport ability, short carrier diffusion lengths (≈70 nm), and high charge recombination rates of BiVO 4 greatly limit its practical PEC performance.…”