Semiconducting biomass-based amorphous carbon films and their potential application in photovoltaic devices

Amorphous carbon (aC) is highly appealing because of its unique structure, electrical and optical properties, making it appropriate for various applications, especially in energy conversion. This work presents a comprehensive study on the synthesis of aC materials, including both intrinsic (i-type) and doped conditions (p- and n-type), to enhance the performance of photovoltaic films. Carbon materials are derived from biomass using a straightforward and environmentally conscious technique. The obtained carbon compound demonstrates an amorphous state with a substantial prevalence of the sp² C=C component. Raman spectroscopy and electron microscopy confirmed the stacking of 2D layers forming a multilayer graphene structure. The carbon compound prepared AC films deposited onto a quartz glass surface via spray coating. The films have a thickness ranging from 247 to 478 nm. The dielectric constants of the optical parameters reveal resonant exciton features at a photon energy of ∼3.8 eV, whereas the real component exhibits semiconductive properties. The refractive indices of the p-, i-, and n-layers, which have gap energies in decreasing order, demonstrate a decline. The optical conductivity of aC is higher than that of amorphous silicon, specifically 0.54 × 10³Ω⁻¹cm⁻¹, 0.48 × 10³ Ω⁻¹cm⁻¹, and 0.53 × 10³ Ω⁻¹cm⁻¹ for the p-, i-, and n-type films, respectively. Based on this outcome, it is reasonable to suggest that the recently developed material is potentially important as a photovoltaic device.