Atomic Layer Deposition of Bismuth Vanadates for Solar Energy Materials

Abstract

The fabrication of porous nanocomposites is key to the advancement of energy conversion and storage devices that interface with electrolytes. Bismuth vanadate, BiVO4 , is a promising oxide for solar water splitting where the controlled fabrication of BiVO4 layers within porous, conducting scaffolds has remained a challenge. Here, the atomic layer deposition of bismuth vanadates is reported from BiPh3 , vanadium(V) oxytriisopropoxide, and water. The resulting films have tunable stoichiometry and may be crystallized to form the photoactive scheelite structure of BiVO4 . A selective etching process was used with vanadium-rich depositions to enable the synthesis of phase-pure BiVO4 after spinodal decomposition. BiVO4 thin films were measured for photoelectrochemical performance under AM 1.5 illumination. The average photocurrents were 1.17 mA cm(-2) at 1.23 V versus the reversible hydrogen electrode using a hole-scavenging sulfite electrolyte. The capability to deposit conformal bismuth vanadates will enable a new generation of nanocomposite architectures for solar water splitting.

Atomic Layer Deposition of Space‐Efficient SnO2 Underlayers for BiVO4 Host–Guest Architectures for Photoassisted Water Splitting

“…Here the UV absorption by the FTO-coated substrates obscures the absorptiono fs uch thin ALD SnO 2 films. Consistent with prior reports, [5,7] the growth of BiVO 4 by surface-functionalized ALD (SF-ALD) resulted in conformal films ( Figure 3). The growth rate here was determined by SEM to be 0.0746 per cycle when grown upon FTOo rS nO 2 .…”

“…Bismuth vanadate has for the past decade been studied asa photoanode for photoelectrochemical (PEC) water splitting, [1] with continuous performance gains over time. [2][3][4][5][6][7][8][9][10][11] The monoclinic scheelite phase( m-BiVO 4 )i st he higheste fficiency allotrope, with ac onduction band edge near 0Vvs. the reversible hydrogen electrode (RHE).…”

BiOI Nanosheets Grown by Chemical Vapor Deposition and Its Conversion to Highly Efficient BiVO4 Photoanode

“…The photocurrent value of 1.5 mA•cm 2 is comparable to the highest photocurrents reported in the literatures for undoped BiVO 4 photoanodes (Table 1). [15][16][17][18][19][20][21][22][23][24][25][26][27] To testify the excellent photoelectrochemical performance of CVD-BiVO 4 electrode, the photoelectrochemical properties were examined in the presence of 1 mol•L 1 sodium sulphite (Na 2 SO 3 ), which served as the hole scavenger. The oxidation of sulphite is thermodynamically and kinetically more favorable than water oxidation, thus sulfite oxidation test enables investigation of the photoelectrochemical properties of BiVO 4 independently of its inherent poor water oxidation kinetics.…”

“…To achieve highly efficient BiVO 4 photoanodes, a considerable amount of work was focused on the preparation of nanostructured BiVO 4 films by low-cost and scalable methods, including spray pyrolysis, chemical vapour deposition (CVD), electrodeposition, dip coating, and seed layer mediated growth. [15][16][17][18][19][20][21][22][23][24][25][26][27] However, the films produced by CVD, dip coating and seed layer growth show poor photoelectrochemical performance. And process of preparing BiVO 4 photoanodes by electrodeposition and annealing is complicated and not eco-friendly.…”

“…1.2× 10 18 ) is enhanced but of the same order of magnitude compared to that of planar film (ca. 0.76×10 18 ), which may also contribute to the enhanced photoelectrochem-ical performance. Therefore, the enhanced PEC performance is a synergistic result of superior visible light absorption, charge transfer property and charge carrier density for the CVD nanoporous BiVO 4 .…”