Mamand Dyari M, Ahmed Bahez Y, Aziz Dara M, Hama Peshawa O, Mohammed Pshko A, Abdalkarim Karzan A, Muhammad Dana S, Hussein Ahang M, Hussen Sarkawt A, Aziz Shujahadeen B, Hassan Jamal
Department of Physics, College of Science, University of Raparin, Sulaymaniyah, Kurdistan, Iraq.
Department of Chemistry, College of Education, University of Sulaimani, Sulaymaniyah, 46001, Kurdistan Region, Iraq.
Spectrochim Acta A Mol Biomol Spectrosc. 2025 Mar 15;329:125485. doi: 10.1016/j.saa.2024.125485. Epub 2024 Nov 27.
This study employed advanced spectroscopic techniques to investigate the structural and optical properties of chitosan (CS) biopolymer films modified with natural dyes from Cosmos Sulphureus Cav. (CSC) flowers. FTIR results indicated that the inclusion of CSC dyes led to broader absorbance and decreased transmittance. Distinct absorption regions were identified, and the optical energy band gap (OEBG), transport gap, and exciton binding energy were calculated using Tauc's method. The OEBG was found to be 5.44 eV for CS while for CS-CSC dye samples, it dropped to 2.24 eV and The Urbach energy increased from 0.44 eV to 0.60 eV, indicating the presence of high tail states in the band gap region. The electron-phonon interaction was found to increase from 11.35 to 15.58. The oscillator energy values (4.13 eV-2.33 eV) at low energies obtained using Wemple-DiDomenico model are found to be close to OEBGs using Tauc's model. Additionally, from the Drude-Lorentz model the N/m* was found to increase from 1.69 × 10 to 1.27 × 10. The third order non-linear polarizability parameter, the linear optical susceptibility and the non-linear index of refractions were all found to increase upon increasing the CSC dye concentrations.
本研究采用先进的光谱技术，研究了用硫磺菊（Cosmos Sulphureus Cav.，CSC）花中的天然染料改性的壳聚糖（CS）生物聚合物薄膜的结构和光学性质。傅里叶变换红外光谱（FTIR）结果表明，加入CSC染料导致吸光度变宽和透光率降低。确定了不同的吸收区域，并使用陶克方法计算了光学能带隙（OEBG）、传输能隙和激子结合能。发现CS的OEBG为5.44电子伏特，而对于CS-CSC染料样品，它降至2.24电子伏特，乌尔巴赫能量从0.44电子伏特增加到0.60电子伏特，表明在带隙区域存在高尾态。发现电子-声子相互作用从11.35增加到15.58。使用温普尔-迪多梅尼科模型在低能量下获得的振子能量值（4.13电子伏特-2.33电子伏特）被发现与使用陶克模型的OEBG接近。此外，根据德鲁德-洛伦兹模型，发现N/m*从(1.69×10)增加到(1.27×10)。发现三阶非线性极化率参数、线性光学极化率和非线性折射率均随着CSC染料浓度的增加而增加。
