## Effect of TiO\({}_{2}\) on Photovoltaics
### Chemical-Photovoltaic Mechanism
#### 2.3.4 Case of Photovoltaic Mechanism after Electrolytic Polymerization and with Light Scattering
\[SPH+e^{-}\to P+H^{+}+S^{-}+e^{-}. \tag{16}\]2  
Hole \(h^{+}\) oxidizes molecules such as rubber or oleic acid, which are defined as \(R\) or \(R\)-\(H\), as shown in Equation (31), and reacts with water as shown in Equations (32) and (33). \[SPH+e^{-}\to P+H^{+}+S^{-}+e^{-}. \tag{16}\]3  
\[SPH+e^{-}\to P+H^{+}+S^{-}+e^{-}. \tag{16}\]4  
\[SPH+e^{-}\to P+H^{+}+S^{-}+e^{-}. \tag{16}\]5  
Hydroxyl radical \(OH^{\bullet}\) in Equation (33) oxidizes \(R\)-\(H\) and reacts with \(H^{\bullet}\) as shown in Equation (14). As a result, molecules such as rubber or oleic acid are oxidized as shown in Equations (31) and (34) [63]. \[SPH+e^{-}\to P+H^{+}+S^{-}+e^{-}. \tag{16}\]6  
The superoxide radicals \(O_{2}^{\bullet-}\) on the right side of Equation (30) are protonated, which means that proton \(H^{+}\) is ionized, thereby generating hydroperoxyl radicals \(HO_{2}^{\bullet}\) as shown in Equation (35). \[SPH+e^{-}\to P+H^{+}+S^{-}+e^{-}. \tag{16}\]7  
Hydrogen peroxide H\({}_{2}\)O\({}_{2}\) is generated as shown in Equation (36) from the hydroperoxyl radicals \(HO_{2}^{\bullet}\) on the right side of Equation (35). \[SPH+e^{-}\to P+H^{+}+S^{-}+e^{-}. \tag{16}\]8In addition, hydrogen peroxide H\({}_{2}\)O\({}_{2}\) is generated as shown in Equation (37) from the hydroperoxyl radicals O\({}_{2}\)\({}^{\bullet-}\) on the right side of Equation (30); the electron in Equation (37) is scavenged by O\({}_{2}\)\({}^{\bullet-}\). \[SPH+e^{-}\to P+H^{+}+S^{-}+e^{-}. \tag{16}\]9  
Summarizing from the above electrochemical reactions in Equations (4) and (5), in the case of light scattering, the creation of the photocurrent can be considered to correspond to the generating electrons as follows:  
1. As shown in Equations (15) and (16), electrons transfer. Electrons are generated not only as shown in Equation (8) through \(S^{-}\) in Equations (15) and (16) but also as shown in Equation (19) through \(H^{+}\) in Equation (16). This chemical-photovoltaic mechanism is irrelevant to the behavior of the rubber molecule. 2. The operations expressed in Equations (19) and (21) are facilitated by the catalyst effect of TiO\({}_{2}\), Ni, and Fe\({}_{3}\)O\({}_{4}\) through the operations shown in Equations (17), (20), and (22). The ones expressed in Equation (10) are also facilitated through the one shown in Equation (18). This chemical-photovoltaic mechanism is irrelevant to the catalyst behavior of TiO\({}_{2}\), Ni, and Fe\({}_{3}\)O\({}_{4}\). 3. Equations (30) and (37) show that electrons are scavenged. This induces the reduction of photovoltaic current. In addition, not only Equations (17) and (18) but also Equations (9), (10), (14), and (19) show that the electrons are generated by water with an aiding catalyst. These summarized results provide the complicated changes in photovoltaic current. This chemical-photovoltaic mechanism is relevant to the behavior of correlation between TiO\({}_{2}\) catalyst and H\({}_{2}\)O. Thus, the photocurrent is created by summarizing the abovementioned operations (a-c) so that the photoelectricity is created as shown in the experimental data (e.g., Figure 7). Incidentally, the photovoltaics of MCF rubber DSSCs are related to the integrated correlation as shown in many equations. The behavior of redox reactions of iodide and triiodide as shown in Equations (1) and (2) with respect to the overall reactions can be guessed via the comparison between Figure 3d,e and the results in our previous study [30] without using dye and electrolyte, as shown in Figure A3 in Appendix A. The role of iodide and the triiodide redox reaction is not diminutive. Furthermore, concerning the chemical-photovoltaic mechanism, we could proceed with the photovoltaic theorem by using the theoretical formula of an equivalent electric circuit and tunneling theory as shown in our previous study [32] with conjugating Equations (1)-(37) in order to clarify the catalyst effect of TiO\({}_{2}\), Ni, and Fe\({}_{3}\)O\({}_{4}\), although we do not present that here.