Additive manufacturing of PEDOT:PSS anode for biophotovoltaic devices

This work delivers a novel anode for biological photovoltaic systems (BPVs) from inkjet-printed conductive poly (3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT:PSS), achieving improved power density (+97 %). BPVs harness photosynthetic microorganisms to generate electricity, requiring an anode to collect charge from the biofilm. Transparent, conductive, and biocompatible, PEDOT:PSS is an ideal candidate to replace transparent conductive oxide anodes. This is the first report analysing feasibility of additively manufactured PEDOT:PSS anodes for BPVs, using inkjet-printing. A competitive sheet resistance (29.5 Ωsq−1) and optical transparency (≈97 %) were achieved. The biocompatibility of inkjet-printed PEDOT:PSS film surface was confirmed with 50 ± 5.6 % occupancy by Leptolyngbya. The long term stability of inkjet-printed PEDOT:PSS anode was determined after no delamination of inkjet-printed PEDOT:PSS film on plastic substrates after 2 years of immersion in growth medium (Blue Green 11, BG11). However, trade-offs exist between optical transparency, electrical resistance, number of printed layers, formulation, and microbial occupancy. These were evaluated to optimise the performance of the inkjet-printed PEDOT:PSS anodes, outperforming Indium Tin Oxide (ITO)-coated Polyethylene Terephthalate (PET) with 97 % higher power density. This study proposes a new approach to fabricate thin-film anodes with surface texture maximising the surface area for microbial attachment, whilst upholding the same spatial area of the BPV device.