Muhammad Dana S, Aziz Dara M, Aziz Shujahadeen B
Department of Physics, College of Education, University of Sulaimani Old Campus, Kurdistan Regional Government Sulaimani 46001 Iraq.
Department of Chemistry, College of Science, University of Raparin Kurdistan Region Ranya 46012 Iraq.
RSC Adv. 2024 Aug 20;14(36):26362-26387. doi: 10.1039/d4ra04228j. eCollection 2024 Aug 16.
The current study employed a novel approach to design polymer composites with modified structural and declined optical band gaps. The results obtained in the present work for polymer composites can be considered an original method to make a new field for research based on green chemistry. Natural dyes extracted from green tea were mixed with hydrated zinc acetate (Zn(CHCOO)·2HO) to produce a metal complex. FTIR results comprehensively established the formation of the Zn-metal complex. The interaction among various components of PVA : Zn-metal complex composite was investigated using FTIR spectroscopy. The non-existence of anion bands of acetate in the Zn-metal complex spectrum confirms the formation of the Zn-metal complex. XRD analysis reveals that the Zn-metal complex improves the amorphous phase of the PVA-based composites. The absorption edge of the doped films shifted towards the lower photon energies. Optical dielectric properties were used to determine /*, , , , , and ; the W-D model was used to calculate , and parameters. The optical dielectric loss parameter was used to determine the optical band gap while the Tauc model was employed to identify various types of electron transitions. The optical energy band gap was 6.05 eV for clean PVA while it decreased to 1 eV for PVA inserted with the Zn-metal complex. The increase in Urbach energy from 0.26 eV to 0.45 eV is an evidence of the boost of amorphous phases in PVA : Zn-metal complex composites. The nonlinear refractive index and the first-order and second-order nonlinear optical susceptibilities were determined. The value of obtained from the W-D model closely matches the optical energy band gap obtained from the Tauc model, which indicates the precision of the analysis in the present study. The increase in SELF and VELF in the composite films establishes that new energy states assigned to the added Zn-metal complex amplify the probability of light-matter interaction.
当前的研究采用了一种新颖的方法来设计具有改性结构和减小光学带隙的聚合物复合材料。在本工作中获得的聚合物复合材料结果可被视为基于绿色化学开辟新研究领域的一种原创方法。从绿茶中提取的天然染料与水合醋酸锌（Zn(CH₃COO)₂·2H₂O）混合以制备金属配合物。傅里叶变换红外光谱（FTIR）结果全面证实了锌金属配合物的形成。使用FTIR光谱研究了聚乙烯醇（PVA）：锌金属配合物复合材料各组分之间的相互作用。锌金属配合物光谱中不存在醋酸根阴离子带证实了锌金属配合物的形成。X射线衍射（XRD）分析表明，锌金属配合物改善了PVA基复合材料的非晶相。掺杂薄膜的吸收边向较低光子能量方向移动。利用光学介电性质来确定/*、 、 、 、 和 ；使用W-D模型计算 、 和 参数。光学介电损耗参数用于确定光学带隙，同时采用陶赫（Tauc）模型来识别各种类型的电子跃迁。纯净PVA的光学能带隙为6.05电子伏特，而插入锌金属配合物的PVA的光学能带隙降至1电子伏特。乌尔巴赫（Urbach）能量从0.26电子伏特增加到0.45电子伏特证明了PVA：锌金属配合物复合材料中非晶相的增加。确定了非线性折射率以及一阶和二阶非线性光学极化率。从W-D模型获得的 值与从陶赫模型获得的光学能带隙紧密匹配，这表明本研究中分析的准确性。复合薄膜中自能（SELF）和振动激发拉曼频移（VELF）的增加表明，归因于添加的锌金属配合物的新能态增加了光与物质相互作用的概率。
