Exploring the optical properties of metal-modified melanin following ultraviolet irradiation: An experimental and theoretical study using density functional theory

Abstract

Melanin has an important function to protect humans from sunlight because of its broad spectrum of light absorption. This characteristic varies according to the nature of absorption and the amount of melanin manufactured. This study focused on UV–Vis absorption of melanin doped with (Fe, Co, Zn) ions. According to the result, eumelanin exhibits substantial absorption in a broad range between (200–500 nm) corresponding to the extension of the violet to the visible region. In the theoretical section of the results, using density functional theory (DFT) revealed an improvement in the optical reactivity properties of transition metals eumelanin. The presence of transition metals led to semiconductor-like behavior and optical reactivity regions in the energy range of 4.4–4.6 electron volts, clearly indicating enhanced structural properties in the presence of metals. In this study, we aspire to investigate the ability to modify the absorption properties of eumelanin can effectively contribute to the treatment of some skin diseases caused by excessive eumelanin secretion.

Keywords

• Eumelanin
• Absorption properties
• UV region
• Transition metals
• Nigella sativa