## Effect of TiO\({}_{2}\) on Photovoltaics
### Chemical-Photovoltaic Mechanism
#### 2.3.4 Case of Photovoltaic Mechanism after Electrolytic Polymerization and with Light Scattering  
In the case of solar cells under scattered light, reverse reactions of Equations (11) and (12) are generated as shown in Equations (15) and (16) under the outer-sphere electron transfer reaction (OSETR), which means that the structural coordination of molecules is not deformed and only the electrons are transferred by the tunneling effect [30]. \[SS+H^{\bullet}+e^{-}\to SH+S^{-}. \tag{15}\]  
\[SPH+e^{-}\to P+H^{+}+S^{-}+e^{-}. \tag{16}\]  
The electron on the left side of Equation (15) transfers from the anode. The electron on the left side of Equation (16) transfers from the anode and that on the right transfers into the cathode. \(S^{-}\) on the right side of Equations (15) and (16) generates the reaction shown in Equation (8), and then the electron on the right side of Equation (8) transfers into the cathode. These transfers are delineated as shown in Figure 8b, which depicts the chemical-photovoltaic mechanism of solar cells. 3.5 Case of Photovoltaic Mechanism by Catalyst Effect of TiO\({}_{2}\), Ni, and Fe\({}_{3}\)O\({}_{4}\). Next, let us consider the catalyst effect of TiO\({}_{2}\), Ni, and Fe\({}_{3}\)O\({}_{4}\). Due to these catalysts, Equations (17) and (18) are created. \[4H^{+}+H_{2}O\to 2H_{2}+O_{2}+4H^{+}. \tag{17}\]  
\[2S^{-}+2H_{2}O\to 2S+H_{2}+2 OH^{-}. \tag{18}\]  
\(H^{+}\) on the right side of Equation (17) creates Equation (19) and then Equation (14). The electron on the left side of Equation (19) transfers from the anode. \(OH^{-}\) on the right side of Equation (18) creates Equation (10). \[H^{+}+e^{-}\to H^{\bullet}. \tag{19}\]  
Additionally, upon electrolytic polymerization, the hydroxyl group of the oleic acid reacts with Ni as shown in Equations (20) and (21). \[2P+Ni\to Ni^{2+}+2\ \ \ C_{17}H_{33}-C\ \ \raisebox{-1.72 pt}{\includegraphics[width=14.226378 pt]{Fig1}}+H_{2}. \tag{20}\]  
\[C_{17}H_{33}-C\ \ \raisebox{-1.72 pt}{\includegraphics[width=14.226378 pt]{Fig1}}+2H^{+}+e^{-} \to\ \raisebox{-1.72 pt}{\includegraphics[width=14.226378 pt]{Fig1}}\ \ \ C_{17}H_{33}\]  
\[C_{17}H_{33}-C\ \ \raisebox{-1.72 pt}{\includegraphics[width=14.226378 pt]{Fig1}}+2H^{+}+e^{-} \to\ \raisebox{-1.72 pt}{\includegraphics[width=14.226378 pt]{Fig1}}\ \ \ C_{0}-OH\ \\[Fe(III)+H_{2}O\rightarrow[FeOH]^{2+}+H^{+}. \tag{25}\]  
\[Fe(II)+OH^{\bullet}\to Fe(III)+OH^{-}. \tag{26}\]  
\[Fe(II)+O_{2}\to Fe(III)+O_{2}^{\bullet-}. \tag{27}\]  
In cases in which ultraviolet light is applied, Equation (28) is generated, followed by Equation (25). Then, Equation (26) is generated. \[SPH+e^{-}\to P+H^{+}+S^{-}+e^{-}. \tag{16}\]0  
\(OH^{-}\) in Equations (23) and (26) creates Equation (14) through Equation (10); the electron on the right side of Equation (10) transfers into the anode via electrolytic polymerization and without light scattering; the electron on the left side of Equation (19) transfers into the cathode via electrolytic polymerization and with light scattering. \(H^{+}\) in Equations (24) and (25) creates Equations (12) and (19). \(H^{\bullet}\) generated by Equation (19) creates Equation (14); the electron on the left side of Equation (19) transfers from the cathode via electrolytic polymerization and without light scattering; the electron on the left side of Equation (19) transfers from the anode via electrolytic polymerization and with light scattering. Regarding other aspects, when the light is irradiated, the reactions below are generated with the TiO\({}_{2}\) catalyst [54; 55; 56; 57; 58; 59]. First, hole \(h^{+}\) and an electron are created from TiO\({}_{2}\) as shown in Equation (29) [60]. \[SPH+e^{-}\to P+H^{+}+S^{-}+e^{-}. \tag{16}\]1  
This electron is scavenged by oxygen, and then superoxide radicals \(O_{2}^{\bullet-}\) are generated as shown in Equation (30) [61; 62].