Deposition of Rhodamine B dye on flexible substrates for flexible organic electronic and optoelectronic: Optical spectroscopy by Kramers-Kronig analysis

Rhodamine B (RhB) films prepared via spin coater on polyacetate flexible substrates. The X-ray diffraction spectroscopy has been done for RhB/polyacetate flexible substrate and displays an amorphous structure of RhB films in the various thicknesses in the range of 74–303 nm. K-K relations used for determining the refractive index and exhibits a normal dispersion at λ > 600 nm and an anomalous dispersion at λ < 600 nm. The electronic transitions reveal two bands of absorbance Q band which due to the first π→π* transitions and Soret band due to the second π→π* transitions. Also, other linear optical constant such as absorption coefficient, band energy gap, dielectric constants, and optical conductivity were discussed. On the other hand, the first (χ⁽¹⁾) and third (χ⁽³⁾) orders of nonlinear optical susceptibilities as well as a nonlinear refractive index (n₂) were calculated and discussed. The electrical and optical conductivities demonstrated the high absorption of RhB/flexible substrates inferring the chance of utilizing these films as optoelectronic gadgets.