Strongly enhanced photocurrent response for Na doped Ta3N5-nano porous structure

Highly ordered nanoporous (nanochannels) Ta2O5 layers were formed by electrochemical anodization of Ta in a glycerol–ethylene glycol mixture containing NH4F and (NH4)2SO4. The layers were then immersed in Na2SO4 and annealed in NH3. This treatment leads to Na-doped Ta3N5 nanostructures that exhibit an apparent band gap of ~ 1.6 eV (compared to 2.1 eV for pure Ta3N5). The doped structure, moreover, shows an almost 10 times higher photoelectrochemical current response in the visible range than pure Ta3N5. This finding represents thus a novel pathway to drastically increase the photoresponse of Ta3N5 which can find wide ranging applications in photoelectrochemical devices.

► The present work reports Na doping at Ta3N5 nanostructures.
► The structures are fabricated by a two step (anodization/annealing) process.
► The doped structures show a drastic increase in the photocurrent response.