A Novel Architecture Based on a Pyrrole-Functionalized Dithieno[3,2-b:2',3'-d]pyrrole (DTP)-Type Conducting Polymer and Thiol-Modified Calixarene Derivative for Biophotovoltaic Solar Cells: Photocurrent and Hydrogen Generations via Both Photosynthesis and Respiratory System.

This review explores the potential of biophotovoltaic devices (BPVs) as a sustainable solution for addressing the global energy crisis and combating climate change. BPVs generate renewable electricity from sunlight and water through the photosynthetic activity of microorganisms such as cyanobacteria and algae, which act as living photocatalysts. The study essentially focuses on improving photocurrent outputs through developing efficient anode materials. An innovative photoanode design is introduced employing cyanobacteria immobilized on a P-(DTP-Ph-Pyr)/Calixarene-AuNP-modified surface. This design features a porous structure conducive to cyanobacterial attachment and efficient electron transfer. As a first step, the conductive polymeric film of 4-(4-(1H-pyrrol-1-yl)-phenyl)-4H-dithieno-[3,2-b:2',3'-d]-pyrrole (DTP-Ph-Pyr) monomer was coated onto a gold electrode via electropolymerization method. Then, a mixture of thiol- and carboxylic group-modified calixarene and gold nanoparticles (AuNPs) was applied to enhance the photoelectrode's performance. The surface of the modified electrode enabled the successful immobilization of Leptolyngbya sp. cyanobacterial cells, providing a reliable interface for efficient photocurrent and hydrogen generation. Calixarenes and their derivatives act as favorable agents for cyanobacterial immobilization due to their specific configurations. Moreover, the formation of covalent bonds between the carboxyl groups of calixarenes and the amino groups in cyanobacteria facilitates the robust immobilization of cyanobacterial cells while maintaining their well-ordered structural integrity and organized cellular architecture. A complementary cathode structure, employing aniline-modified Pt nanoparticles, facilitates the reduction of protons to generate hydrogen gas. Overall, this study underscores the promise of BPVs as feasible clean energy technologies and introduces innovative methods to improve their efficiency and sustainability.