Understanding the optical behaviours and the power conversion efficiency of novel organic dye and nanostructured TiO2 based integrated DSSCs

Abstract

The rapid use of fossil fuels has led to quick industrialization, swift economic growth, improved living standards, a high release of greenhouse gas, and fast exhaustion of fuel resources, which is a big threat to the environment and climate changes. To keep the planet green, dye-sensitized solar cells (DSSCs) have attracted much attention as the third-generation solar cells. This article documented an extensive study on the efficient use of natural dyes (Portulaca grandiflora, pereskia bleo, and alternanthera ficoidea), mesoporous TiO2 photoanode, a carbon cathode, and conductive layers to improve efficiency of DSSCs at ambient conditions. All of the conductive/TiO2/natural dyes display enhanced structural, optical, and electrical properties. X-ray diffraction studies of conductive/TiO2 layers represent the tetragonal structure which is buttressed by the SEM imaging, whereas organic dyes are amorphous in nature. The integrated conductive/TiO2/natural dye films have good sensitization in the visible spectrum (380–750 nm) and possess a bandgap falling (1.25–1.50 eV) and high refractive index while the maximum optical conductivity is observed in pereskia bleo. On the other hand, alternanthera ficoidea and portulaca grandiflora exhibit higher electrical conductivity (7.5 × 1012 Scm−1) and optical electronegativity (1.777). The TiO2 photoanodes at a conductive layer thickness of 3886.8 nm with iodide/tri-iodide redox liquid electrolyte generated current densities of 0.071–0.106 mAcm−2 under AM 1.5 illumination. Furthermore, the short-circuit photocurrent density (JSC), open-circuit voltage (VOC), fill factor (FF), and the corresponding photon-to-current conversion efficiency (η) estimated from the J-V characteristic curves with an effective area of 1 cm2 calculated for pereskia bleoDSSC are JSC = 0.106 mAcm−2, VOC = 0.023 V,FF = 45, andη = 0.11%. This study will open up a new door to fabricate highly efficient solar cells by modifying different parameters (photoanode, conductive layer, hybrid active layer, or different electrolyte) that can achieve meaningful success in photovoltaic industries.