Fig. 3.

Dark and photocurrent characteristics. a IV-characteristic of the FTO/BiVO₄/probe circuit under illumination and in dark for PtIr-coated and Au-coated probes at the same sample position. b Current density under illumination for PtIr-coated and Au-coated probe calculated using the corresponding contact area between probe and BiVO₄. We used the Derjaguin–Mueller–Toporov continuum mechanical model to estimate the contact area between the surface and the probe³⁴. All IV-curves show strong nonlinear behavior, thereby excluding ohmic contact and wiring resistance as limiting factors in overall electronic transport through the photoanode device