## 1 Introduction
Therefore, NR-latex can be electrolytically polymerized in a very short time interval. The alignment of the magnetic clusters enhances the photovoltaic properties as well as electric and thermal conductivity. In addition, the polyisoprene of the NR-latex, oleic acid, and water molecules play the roles of p- and n-type semiconductors, as indicated in the first report. Therefore, the MCF rubber solar cell has been shown to have piezoelectric properties based on the built-in voltage of the semiconductor [26], and photovoltaic properties based on the semiconductor. The former is comparable to piezoelectric-like behavior and the latter to solar cell-like one. In addition, it is elucidated that the combination of NR-latex as a water-soluble rubber and TiO\({}_{2}\) particles could have a photovoltaic effect since the combination of water and TiO\({}_{2}\) has been reported to have a photovoltaic effect with electrochemical photolysis (called the Honda-Fujishima effect) [27]. Therefore, the composite synthesized by NR-latex, MF and TiO\({}_{2}\) particles produces both photovoltaics and piezoelectricity. In the first report, the principle of generated photovoltaics of a dry-type MCF solar cell rubber, which is both a photovoltaic and piezoelectric material, was described using a chemical-physical model. On the basis of this principle, the experimental results obtained in the first report are discussed together with the physical and chemical interpretation. Whether the surface condition of the MCF solar cell rubber is damp or not is a significant factor. \"Dry type\" refers to dry-produced solar cells: the MCF rubber is vulcanized so that this results in dry rubber solar cells because heat is generated by electrolytic polymerization [28]; the dye and electrolyte are not deposited on the MCF rubber so that they are involved in the MCF rubber liquid before vulcanization. The first report dealt with the dry-type solar cell. In contrast, the resulting solar cell is denoted as \"wet type\" such as the Gratzel-type solar cell. Naturally, the addition of dye and electrolyte as a wet-type solar cell may be expected to enhance the photovoltaic effect because the dye seeps into the electrolytically polymerized MCF rubber and photovoltaic power is generated by a redox reaction. At the onset of the present report, we deal with wet-type MCF rubber solar cells and discuss the photovoltaic effect by a comparison between dry- and wet-types. In the present report, we investigate the effect of several factors on the MCF rubber solar cell under conditions without tension and compression. In the first report, the dry-type MCF rubber solar cell induced a relatively small electric current density. This result was influenced by other experimental conditions such as the kind of sensitized dye and the kind of electrode material caused in work function. Therefore, we argue that these factors of experimental conditions are significant without tensing and compressing a wet-type MCF rubber solar cell. Next, the effect of simultaneously existing tension and compression on the photovoltaics of wet-type MCF rubber solar cell is investigated in this report. In the first report, we dealt with the experimental condition of only compression within a small pressure range, and the case of tension effect on the MCF rubber solar cell was not evaluated. The present report deals with large compression as well as tension. On the other hand, in the field of robotics, the condition of simultaneously existing tension and compression is sufficiently significant to warrant the further development of MCF rubber solar cells, because the artificial skin installed in a robot would be elongated and compressed simultaneously in most instances. We then explore the effect of simultaneous excitation of tension and compression on the hybrid properties of photoelectricity (photovoltage and photocurrent) and piezoelectricity in the MCF rubber solar cell. Finally, we investigate the effect of electrodes location on the changes in voltage and electric current by illumination.