Nontransparent contact fingers on the sun-facing side of solar cells represent optically dead regions which reduce the energy conversion per area. We consider two approaches for guiding the incident light around the contacts onto the active area. The first approach uses graded-index metamaterials designed by two-dimensional Schwarz–Christoffel conformal maps, and the second uses freeform surfaces designed by one-dimensional coordinate transformations of a point to an interval.

Two natural dyes containing anthocyanin are extracted from sour and sweet pomegranate from Iran. Spectrophotometric evaluation of the natural dyes in solution and on a TiO2 substrate was carried out to assess changes in the status of the natural dyes. The results show that the natural dyes indicate buthochromic shift on the TiO2 substrates. Dye-sensitized solar cells (DSSCs) are fabricated to determine the photovoltaic behaviour of each dye and the mixture of extracts.