Impact of light intensity and electrolyte volume on performance of photo-electrochemical (PEC) solar cell

The world’s energy demand is continuously increasing. Non-renewable energy sources, such as petroleum and coal, are extremely limited. On the other hand, conversion efficiency of renewable energy sources into useful forms is insufficient. In our study, we pursued methods to make more efficient solar cells – in particular, photo-electrochemical (PEC) solar cells. We selected the Molybdenum diselenide (MoSe₂) based PEC solar cell because of its high resistance to corrosion. First, we explored the relationship between light intensity and efficiency of PEC solar cells. We expected that corrosion of the PEC solar cell would increase with increase in intensity of incident light. Thus, we hypothesized that the efficiency of the solar cell would decrease with increased intensity of incident light. Further, we investigated the relationship between solar cell efficiency and electrolyte volume. We hypothesized that efficiency of PEC solar cell would increase as the electrolyte volume increased. We analyzed several parameters— such as light intensity, fill factor, efficiency, etc.—to draw conclusions. First, we found that percentage efficiency of PEC solar cell was proportional to (light intensity)^-0.9. Further analysis showed that PEC solar cell performance was positively influenced by increasing the electrolyte volume. Data revealed that this increase in solar cell performance was more consequential at low intensities of light (around 10 mW/cm²). Our study could contribute to improving the quality of PEC solar cells and might help in the development of carbon-free hydrogen economy.