Figures (3)  Tables (2)

    • Figure 1. 

      Properties and applications of fungal melanin pigment.

    • Figure 2. 

      Composite biohybrid cell with enhanced conducting properties.

    • Figure 3. 

      Light harvesting and redox-driven electron transfer in biohybrid cells.

    • Biological component Representative examples Primary function Photovoltaic/bioelectronic role Advantages
      Melanin pigments Eumelanin, DHN-melanin Broadband light absorption, redox cycling Photosensitizer, hole-transport layer, interfacial stabilizer, UV-protective coating UV–Vis–NIR absorption, photostability, mixed ionic–electronic conductivity
      Carotenoids β-carotene, torulene, astaxanthin Visible-light absorption, photoprotection Auxiliary photosensitizer, ROS quencher Improves stability, reduces photodegradation
      Quinone pigments Anthraquinones, naphthoquinones Reversible redox reactions Natural dyes, electron mediators Stable redox cycling, visible-light activity
      Azaphilone pigments Polyketide-derived azaphilones Tunable optical absorption Spectral tuning in photoactive layers High photochemical stability
      Phenolic metabolites Phenolic acids, polyphenols Electron donation, antioxidant activity Electron shuttles, interface protection Reduces recombination and oxidative damage
      Flavonoids Flavones, flavonols Redox mediation Charge-transfer intermediates Stabilizes charge-separated states
      Terpenoids Mono- and sesquiterpenes Metal interaction, redox modulation Interface modifiers Enhances semiconductor interaction
      Polyketides Aromatic polyketides Electron transfer Photoredox mediators Chemical versatility
      Laccases Multicopper oxidases Oxidation of aromatic compounds Electrode surface modification, polymerization Green catalysis, surface functionalization
      Peroxidases Mn-peroxidase, lignin peroxidase Strong oxidation reactions Pigment modification, interface tuning Broad substrate specificity
      Oxidoreductases NADH/NADPH-dependent enzymes Metal ion reduction Green synthesis of nanoparticles Mild conditions, uniform nanomaterials
      Biogenic nanoparticles Ag, Au, TiO2, ZnO, CdS Light scattering, charge transport Photoelectrodes, interfaces Enhanced compatibility, eco-friendly synthesis
      Melanized hyphae Pigmented fungal cell walls Electron conduction Biological charge-transport pathways Semiconductive behavior
      Hyphal networks Filamentous fungal structures Spatial electron transport Conductive scaffolds Large surface area, structural flexibility

      Table 1. 

      Biological components of fungal endophytes and their functional roles in biohybrid photovoltaic systems.

    • Category Key elements Description/role Current status Future direction
      Electrode materials Carbon cloth, graphene, CNTs Conductive, biocompatible substrates Widely used Nano-structured optimization
      Metal-oxide semiconductors TiO2, ZnO Electron injection and transport Proven in DSSCs Band alignment tuning
      Conductive polymers PANI, PPy, PEDOT : PSS Flexible charge-transport layers Emerging Composite enhancement
      Immobilization matrices Hydrogels, bioinks, porous scaffolds Stabilize biomolecules Actively developed Printable large-area devices
      Device architectures DSSCs, hybrid PV–biofuel cells Light-to-electric/chemical
      energy conversion      		 Proof-of-concept Integrated multifunctional systems
      Light-harvesting mechanism Pigment photochemistry Non-photosynthetic absorption Demonstrated Spectral optimization
      Electron transfer pathways Redox mediation, hyphal conduction Charge transport without photosystems Functional but low efficiency Engineered conductivity
      Power conversion efficiency Typically < 1% Lower than silicon PV Limited Hybrid enhancement
      Stability UV and oxidative tolerance Better than many organic dyes Moderate Advanced encapsulation
      Scalability Fermentation-based production Renewable, low-energy Developing Industrial bioprocessing
      Batch variability Growth-condition dependence Limits reproducibility Major challenge Controlled bioreactors
      Biosafety Non-pathogenic strains preferred Manageable risk Addressed via purification Standardized safety protocols
      Engineering solutions Genetic engineering, composites Performance enhancement Rapid progress CRISPR-based optimization
      Additive manufacturing Bioinks, 3D printing Structural control Early-stage Large-area fabrication
      Target applications Sensors, agriculture, wearables Low-power energy needs Highly suitable Decentralized energy systems
      Sustainability Biomass-based materials Low carbon footprint Strong advantage Life-cycle optimization

      Table 2. 

      Materials, device architectures, performance, challenges, and applications of fungal endophyte-based photovoltaic systems.