Figure 5. Typical Raman spectrum of sepia melanin.

From

Natural Dye Sensitizer for Grӓtzel Cells: Sepia Melanin

Agnes Mbonyiryivuze, Isaiah Omollo, Balla Diop Ngom, Bonex Mwakikunga, Simon Mokhotjwa Dhlamini, Eugene Park, Malik Maaza

Physics and Materials Chemistry. 2015, 3(1), 1-6 doi:10.12691/pmc-3-1-1