Comprehensive assessment of the Calotropis procera natural dye extracts with weather effects for photovoltaic solar cell manufacturing

This work studies the Calotropis procera, a xerophytic plant of the hyper-arid hot deserts of the Gulf region, as a model to assess correlations between environmental conditions and photosynthetic efficiency. Plant structure and environmental factors are thoroughly assessed, such as leaf surface orientation, daytime, and photosynthetic photon flux density (PPFD). The latter measures effect of incident light on leaf surface on the photosynthesis efficiency of Calotropis, and consequently the performance of a solar cell. Furthermore, the linear Angstrom model is developed to correlate solar irradiance and sunlit hours with the quality of incident radiation on cell performance. It was interesting to note that leaves facing east and south directions received higher incident light and temperatures, attained lower potential quantum efficiency and operating efficiency but higher values of nonphotochemical chlorophyll fluorescence quenching. Such results indicate that the loss of excess excitation energy was insufficient to enhance the photosynthesis efficiency in these directions. The dye extracts were used to build a dye-sensitized solar cells that were compared to ones using synthetic ruthenium dye. The Calotropis photosystem demonstrated lower efficiencies (0.157% vs 1.58% from Ru cells). Nevertheless, for the Calotropis-based cells, a figure-of-merit of cell efficiency over their production cost makes them a good candidate for research and development efforts to overcome obvious drawbacks of low efficiency and stability.