Hybrid Microwave Annealing for Fabrication of More Efficient Semiconductor Photoanodes for Solar Water Splitting

Abstract

Hybrid microwave annealing (HMA) is proposed as an alternative to conventional thermal annealing (CTA) in a furnace to fabricate efficient semiconductor photoelectrodes for solar water splitting. Thus, the effects of HMA are investigated in comparison with CTA using spinel zinc ferrite as an example. The ZnFe2O4 photoanodes fabricated by HMA with a graphite susceptor provide less defective surface, better structural ordering and smaller feature size than photoanodes prepared by CTA. Besides, HMA does not impair conductivity of the F:SnO2 glass substrate. All these positive factors of HMA leads to ∼4 times higher photocurrents at 1.23 VRHE and lowered onset potential by ∼100 mV under 1 sun irradiation of an optimized ZnFe2O4 photoanode relative to that fabricated by CTA. The HMA could be an effective generic method to fabricate efficient photoelectrodes based on refractory semiconductors replacing incumbent CTA.