Understanding the optical behaviours and the power conversion efficiency of novel organic dye and nanostructured TiO_2 based integrated DSSCs

摘要

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 x 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 (eta) estimated from the J-V characteristic curves with an effective area of 1 cm(2) calculated for pereskia bleo DSSC are J(SC) = 0.106 mAcm(-2), V-OC = 0.023 V, FF = 45, and eta = 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.