Interface engineering of Ta3N5 thin film photoanode for highly efficient photoelectrochemical water splitting

Abstract

Interface engineering is a proven strategy to improve the efficiency of thin film semiconductor based solar energy conversion devices. Ta3N5 thin film photoanode is a promising candidate for photoelectrochemical (PEC) water splitting. Yet, a concerted effort to engineer both the bottom and top interfaces of Ta3N5 thin film photoanode is still lacking. Here, we employ n-type In:GaN and p-type Mg:GaN to modify the bottom and top interfaces of Ta3N5 thin film photoanode, respectively. The obtained In:GaN/Ta3N5/Mg:GaN heterojunction photoanode shows enhanced bulk carrier separation capability and better injection efficiency at photoanode/electrolyte interface, which lead to a record-high applied bias photon-to-current efficiency of 3.46% for Ta3N5-based photoanode. Furthermore, the roles of the In:GaN and Mg:GaN layers are distinguished through mechanistic studies. While the In:GaN layer contributes mainly to the enhanced bulk charge separation efficiency, the Mg:GaN layer improves the surface charge inject efficiency. This work demonstrates the crucial role of proper interface engineering for thin film-based photoanode in achieving efficient PEC water splitting.

Water oxidation of visible-light-responsive bismuth-yttrium oxychloride promoted by a dual-ion doping strategy for assembly of Z-scheme overall water splitting

“…34 12 had the smallest diameter, demonstrating the least interfacial charge-transfer resistance. 35 As shown in Fig. 5c, the characteristic emission peak (ca.…”

Recent research progress on operational stability of metal oxide/sulfide photoanodes in photoelectrochemical cells

“…Fourth, photogenerated holes generated by light are transferred to the semiconductor surface and undergo an oxidation reaction with water during PEC testing. If the photogenerated holes accumulate for various reasons (such as interface recombination or excessive surface states) at this time, the holes photogenerated too late to transfer will generate oxidation reactions with the semiconductor material, causing deactivation of the photoanode [42].…”

Crystal facet and phase engineering for advanced water splitting

“…However, its relatively positive band edge position causes anodic onset potentials, and the photoinduced surface oxidation weakens stability. [140][141][142] Also, since Ta 3 N 5 is synthesized from TaO x by the nitridation, the substitution of oxygen for nitrogen changes the unit cell volume, forming the defects. Such defect formation makes the fabrication of single crystals and crystal facet engineering difficult.…”