Titanium dioxide/agglomerated-free reduced graphene oxide hybrid photoanode film for dye-sensitized solar cells photovoltaic performance improvement

In this work, the role of agglomerated-free reduced graphene oxide (rGO) in the modification of titanium dioxide (TiO2) photoanode film was investigated for the enhancement of photovoltaic performance in dye-sensitized solar cells (DSSCs). The rutile TiO2 nanorods–nanoflowers (NRs–NFs) and the photoanode layer consisting of anatase TiO2 nanoparticles (NPs) were synthesized by the simple hydrothermal growth and squeegee method, respectively. Post-annealing treatment of TiO2 NRs–NFs was also done in order to investigate its effect on the DSSCs performance. Meanwhile, the rGO solution was produced by reducing a graphene oxide (GO) solution utilizing hydrazine hydrate via a chemical reduction process. The initial GO solution was synthesized by electrochemical exfoliation assisted by a hyper-branched sodium 1,4-bis (neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate (TC14) surfactant. The produced TC14-rGO was also hybridized with multi-walled carbon nanotubes (MWCNTs), which then coated by thin platinum (Pt) NPs (TC14-rGO_MWCNTs/Pt) and used as counter electrode (CE) thin film. Based on solar simulator measurements, the highest energy conversion efficiency ( η ) (1.559%) was achieved by TiO2 NRs–NFs/TC14-rGO/TiO2 NPs hybrid photoanode film with the short current density ( J s c ), open circuit voltage ( V o c ), and fill factor (FF) of 3.275 mA/cm2, 0.747 V, and 53.5, respectively as compared to others fabricated photoanode films; non-ann TiO2 NRs–NFs/TiO2 NPs (1.215%), ann TiO2 NRs–NFs/TiO2 NPs (1.462%), and TiO2 NRs–NFs/TiO2 NPs/TC14-rGO (0.525%). This result shows that the utilization of TC14-rGO for both photoanode and CE film increases the conductivity of the film. High η was also supported by high dye adsorption promoted by TiO2 NPs as the top photoanode layer.