A Study on the Optoelectronics Parameters of Natural Dyes Extracted From Beetroot, Cabbage, Walnut and Henna For Potential Applications in Organic Electronics

In this work, the optoelectronic parameters of natural dyes extracted from beetroot, red cabbage, walnut leaves, and henna are determined and investigated. These include optical energy gap (Eg), extinction coefficient (k), refractive index (n), dielectric constant ( εr ) and optical conductivity ( σr ). Results showed that cabbage dye exhibited a maximum values of n=6.08, εr = 37.18 and σr = 13.92 * 10-3S/cm, while henna dye presented the lowest values of n = 1.19, εr = 1.5 and σr = 0.039 * 10-3S/cm compared to the optoelectronic parameters of the other studied samples. The optical absorption in the dyes were found to obey a direct allowed transition between the molecular energy levels. The results presented here can be of a special importance for some potential applications in organic electronics such as organic photovoltaics and sensors.