Photoelectric Current Enhancement via Millimeter-Scale Bioelectrochemical Cell Using Iron Oxide Nanoparticles-Modified Screen-Printed Electrodes

Herein, photocurrent generating a millimeter-scale bioelectrochemical cell (mBEC) is fabricated using a thylakoid membrane (TM) on a screen-printed electrode (SPE). The mBEC is used to generate a direct and mediated photocurrent without using a selective membrane. The mediated photocurrent generation is tested with iron oxide nanoparticles (NPs) coated on the SPE surface and the water soluble mediators potassium hexacyanoferrate (FCN) and p-Benzoquinone (BQ). The SPE/TM system produces a 4.35 μA cm⁻² photocurrent without using a mediator obtained by direct electron transfer (DET). A significant enhancement reaches the current generation when an efficient amount of mediator is used in the system. The SPE/NP/BQ/TM system produces a 55 μA cm⁻² photocurrent with an incorporation among TM, NP, and BQ. The performance of the mBECs is tested by taking the measurements from series and parallel connected cells. An enhanced photocurrent generation of 178 μA cm⁻² is attained when the four cells are connected in series. Also, a higher light conversion rate is achieved by the parallel connected two cells. In addition, the maximum current density of mBEC obtained from the SPE/NP/BQ/TM cell at a pseudo-steady state is 180 mA m⁻² at a power density of 40 mWm⁻².