Comparative Study of TiO(2), ZnO, and Nb(2)O(5) Photoanodes for Nitro-Substituted Naphthoquinone Photosensitizer-Based Solar Cells

[Image: see text] This research focuses on the first demonstration of NO(2)Lw (2-hydroxy-3-nitronaphthalene-1,4-dione) as a photosensitizer and TiO(2), ZnO, and Nb(2)O(5) as photoanode materials for dye-sensitized solar cells (DSSCs). The metal-free organic photosensitizer (i.e., nitro-group-substituted naphthoquinone, NO(2)Lw) was synthesized for this purpose. As a photoanode material, metal oxides, such as TiO(2), ZnO, and Nb(2)O(5), were selected. The synthesized NO(2)Lw contains an electron-withdrawing group (−NO(2)) and anchoring groups (−OH) that exhibit absorption in the visible range. The UV–visible absorbance spectrum of NO(2)Lw demonstrates the absorption ascribed to ultraviolet and visible region charge transfer. The NO(2)Lw interacts with the TiO(2), ZnO, and Nb(2)O(5) photoanode, as shown by bathochromic shifts in wavelengths in the photosensitizer-loaded TiO(2), ZnO, and Nb(2)O(5) photoanodes. FT-IR analysis also studied the bonding interaction between NO(2)Lw and TiO(2), ZnO, and Nb(2)O(5) photoanode material. The TiO(2), ZnO, and Nb(2)O(5) photoanodes loaded with NO(2)Lw exhibit a shift in the wavenumber of the functional groups, indicating that these groups were involved in loading the NO(2)Lw photosensitizer. The amount of photosensitizer loading was calculated, showing that TiO(2) has higher loading than ZnO and Nb(2)O(5) photoanodes; this factor may constitute an increased J(SC) value of the TiO(2) photoanode. The device performance is compared using photocurrent–voltage (J–V) curves; electrochemical impedance spectroscopy (EIS) measurement examines the device’s charge transport. The TiO(2) photoanode showed higher performance than the ZnO and Nb(2)O(5) photoanodes in terms of photoelectrochemical properties. When compared to ZnO and Nb(2)O(5) photoanodes-based DSSCs, the TiO(2) photoanode Bode plot shows a signature frequency peak corresponding to electron recombination rate toward the low-frequency region, showing that TiO(2) has a greater electron lifetime than ZnO and Nb(2)O(5) photoanodes based DSSCs.