Efficient and Stable Silicon Microwire Photocathodes with a Nickel Silicide Interlayer for Operation in Strongly Alkaline Solutions

Wouter Vijselaar, Roald M. Tiggelaar, Han Gardeniers, Jurriaan Huskens (Corresponding Author)

Research output: Contribution to journalArticleAcademicpeer-review

33 Citations (Scopus)
141 Downloads (Pure)

Abstract

Most photoanodes commonly applied in solar fuel research (e.g., of Fe2O3, BiVO4, TiO2, or WO3) are only active and stable in alkaline electrolytes. Silicon (Si)-based photocathodes on the other hand are mainly studied under acidic conditions due to their instability in alkaline electrolytes. Here, we show that the in-diffusion of nickel into a 3D Si structure, upon thermal annealing, yields a thin (sub-100 nm), defect-free nickel silicide (NiSi) layer. This has allowed us to design and fabricate a Si microwire photocathode with a NiSi interlayer between the catalyst and the Si microwires. Upon electrodeposition of the catalyst (here, nickel molybdenum) on top of the NiSi layer, an efficient, Si-based photocathode was obtained that is stable in strongly alkaline solutions (1 M KOH). The best-performing, all-earth-abundant microwire array devices exhibited, under AM 1.5G simulated solar illumination, an ideal regenerative cell efficiency of 10.1%.
Original languageEnglish
Pages (from-to)1086-1092
JournalACS Energy Letters
Volume3
Issue number5
DOIs
Publication statusPublished - May 2018

Keywords

  • UT-Hybrid-D

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