3D Printing of Thylakoid-PEDOT:PSS Composite Electrode for Bio-Photoelectrochemical Cells

Abstract

Thylakoid membranes (TMs) isolated from plant cells produce high-energy electrons by splitting water molecules using solar energy during photosynthesis. Since those photosynthetic electrons (PEs) can be harvested by oxidizing TMs, various approaches to attach TMs on electrodes have been investigated so far. Here, we propose embedding of TMs in the electrically conductive polymeric structure using 3D printing. A photosynthetic and electrically conductive ink based on a mixture ink of TMs and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) was developed and 3D printed as lattice structures. This approach allows for more stable physical and electrochemical interfacing between TMs and the conductive polymer. Furthermore, free-form 3D structures, which can harvest PEs, can be constructed by 3D printing. 3D printing conditions for the TM/PEDOT:PSS inks were optimized, and 3D printed lattice electrodes with different geometries were analyzed in terms of light absorption and PE extraction. We found out that TM-embedded offset-stack lattice electrodes generated the highest PE current density of 70.6 μA/cm2. A bio-photoelectrochemical cell based on the TM-embedded offset-stack lattice generated a short-circuit current density of 0.57 mA/cm2 and a maximum power density of 101.7 μW/cm2.

MnO2-decorated highly porous 3D-printed graphene supercapacitors for photosynthetic power systems

“…70–78 Regarding the PE current density of this system, the highest PE current density among recent studies was achieved in this work as shown in Fig. S7 † 10–14,29–33,79–84.…”

“…S7. † [10][11][12][13][14][29][30][31][32][33][79][80][81][82][83][84] For efficient collection of PEs from TMs, TMs need to be attached and electrically connected to a 3D printed graphene electrode. However, since TMs have abundant ionized side groups, they do not form stable bonds with graphene electrodes that are hydrophobic.…”

“…Then, the PEs are electrochemically transported through a photosynthetic electron transfer (PET) chain consisting of various photosynthetic apparatuses such as photosystem II (PSII), plastoquinone pools, cytochrome complexes and photosystem I (PSI) in the thylakoid membrane (TM). 3 For the last decade, extraction of PEs from PETs has been extensively studied as a promising environmentally friendly and sustainable energy conversion technology using TMs, [4][5][6][7][8][9][10][11][12][13][14] algal cells, [15][16][17][18] cyanobacterium, 19 PSI, [20][21][22][23] and PSII. 24,25 Among these attempts, TM-based PE harvesting has been extensively investigated because of the long-term stability and the abundance of photosynthetic apparatus in TMs.…”

“…26,27 To enhance the efficiency of PE harvesting from TMs, functional nanomaterials were integrated with TMs, such as graphene oxide (GO), 11,28,29 carbon nanotubes (CNTs), 12,13,30 osmium redox polymers, 6,10,12 Au nanoparticles, 31 and ruthenium oxide (RuO 2 ). 32 The effects of electrode materials and geometry on PE harvesting were also investigated with carbon, 4,12 conductive polymers, 7,14 metal oxides, 32 or micro-pillar structures. [33][34][35] Recently, a novel concept of self-charging supercapacitive biosolar cells has been introduced, in which solar energy is converted into PEs and simultaneously stored without the aid of any external storage system.…”

“…26,27 To enhance the efficiency of PE harvesting from TMs, functional nanomaterials were integrated with TMs, such as graphene oxide (GO), 11,28,29 carbon nanotubes (CNTs), 12,13,30 osmium redox polymers, 6,10,12 Au nanoparticles, 31 and ruthenium oxide (RuO 2 ). 32 The effects of electrode materials and geometry on PE harvesting were also investigated with carbon, 4,12 conductive polymers, 7,14 metal oxides, 32 or micro-pillar structures. 33–35…”