Thin Film Laboratory, Physics Department, Faculty of Education, Ain Shams University, Heliopolis, Roxy, Cairo 11757, Egypt.
Spectrochim Acta A Mol Biomol Spectrosc. 2011 Nov;82(1):467-74. doi: 10.1016/j.saa.2011.07.079. Epub 2011 Jul 30.
Spectral-optical-electrical-thermal properties of deposited thin films of nano-sized calcium(II)-8-hydroxy-5,7-dinitroquinolate complex, Ca[((NO(2))(2)-8HQ)(2)], were explored, studied and evaluated in this work. Thin films of Ca[((NO(2))(2)-8HQ)(2)] were assembled by using a direct, simple and efficient layer-by-layer (LBL) chemical deposition technique. The optical properties of thin films were investigated by using spectrophotometric measurements of transmittance and reflectance at normal incidence in the wavelength range 200-2500 nm. The refractive index, n, and the absorption index, k, of Ca[((NO(2))(2)-8HQ)(2)] films were determined from the measured transmittance and reflectance. The real and imaginary dielectric constants were also determined. The analysis of the spectral behavior of the absorption coefficient in the intrinsic absorption region reveals a direct allowed transition with band gaps of 1.1 eV and 2.4 eV for the optical and transport energy gaps, respectively. The current-voltage characteristics of Ca[((NO(2))(2)-8HQ)(2)] showed a trap-charge limited conduction in determining the current at the intermediate and high bias regimes. Graphical representation of the current-voltage characteristics yields three distinct linear parts indicating the existence of three conduction mechanisms. Structural characterization and identification were confirmed by using Fourier transform infrared spectroscopy (FT-IR). Scanning electron microscopy (SEM) was also used to image the surface morphology of the deposited nano-sized metal complex and such study revealed a high homogeneity in surface spherical particle distribution with average particles size in the range 20-40 nm. Thermal gravimetric analysis (TGA) was also studied for [(NO(2))(2)-8HQ] and Ca[((NO(2))(2)-8HQ)(2)] to evaluate and confirm the thermal stability characteristics incorporated into the synthesized nano-sized Ca[((NO(2))(2)-8HQ)(2)] complex.
本工作研究并评价了纳米尺寸钙（II）-8-羟基-5,7-二硝基喹啉配合物，Ca[((NO(2))(2)-8HQ)(2)]，沉积薄膜的光谱-光学-电学-热性能。使用直接、简单且高效的层层（LBL）化学沉积技术组装 Ca[((NO(2))(2)-8HQ)(2)]薄膜。通过在 200-2500nm 波长范围内进行正常入射的分光光度透射率和反射率测量，研究了薄膜的光学性质。从测量的透射率和反射率确定 Ca[((NO(2))(2)-8HQ)(2)]薄膜的折射率 n 和吸收指数 k。还确定了真实和虚介电常数。吸收系数在本征吸收区域的光谱行为分析表明，光学和输运能隙的直接允许跃迁分别具有 1.1eV 和 2.4eV 的带隙。Ca[((NO(2))(2)-8HQ)(2)]的电流-电压特性表明，在中间和高偏压区域确定电流时存在陷阱电荷限制传导。电流-电压特性的图形表示产生三个明显的线性部分，表明存在三种传导机制。傅里叶变换红外光谱（FT-IR）用于确认结构特征和鉴定。还使用扫描电子显微镜（SEM）对沉积的纳米尺寸金属配合物的表面形貌进行成像，该研究表明表面球形颗粒分布具有高度均匀性，平均颗粒尺寸在 20-40nm 范围内。还对 [(NO(2))(2)-8HQ]和 Ca[((NO(2))(2)-8HQ)(2)]进行了热重分析（TGA），以评估和确认合成的纳米尺寸 Ca[((NO(2))(2)-8HQ)(2)]配合物中包含的热稳定性特征。
