Study of Electric Properties of rGO/Fe<sub>3</sub>O<sub>4 </sub>Nanocomposites and their Potential Applications as Counter Electrode of Dye-Sensitized Solar Cells

rGO/Fe 3 O 4 nanocomposites were prepared through the solid-state technique by adjusting FeCl 2 and FeCl 3 volumes (1, 2, 3, 4, and 5 ml). The structural, chemical, morphological, and optical properties of the nanocomposites were investigated using XRD, FTIR, SEM, and UV-Vis Spectroscopy. The synthesized rGO/Fe 3 O 4 nanocomposite was deposited on an FTO substrate through drop coating to fabricate a CE plate, which was then tested using a solar simulator with FTO/TiO 2 serving as the photoanode. The XRD patterns of the rGO/Fe 3 O 4 nanocomposite showed consistency with COD data number 3000327. Calculations using Debye's Scherrer equation demonstrated that Fe 3 O 4 crystal size diminished as Fe 3 O 4 concentration increased. The FTIR analysis confirmed the existence of C=C and Fe-O bonds, characteristic of rGO and Fe 3 O 4 particles' functional groups. As FeCl 2 and FeCl 3 concentrations increased from 1 ml to 5 ml, the band gap energy of the rGO/Fe 3 O 4 nanocomposite expanded from 3.14 eV to 3.39 eV. This band gap energy expansion correlated with improved DSSC solar cell performance, with efficiency increasing from 0.003% (RF1) to 0.097% (RF5), suggesting catalytic activity supporting electrolyte regeneration in DSSC solar cells.