Optical absorption studies of copper phthalocyanine thin films
- 作者：A. A.M. Farag
- 关键词：Optical absorption ; CuPc ; Thin film
- 刊名：Optics and Laser Technology
- 出版年：2007
- 期刊代码：48_00303992
- 类别：ph
- 出版时间：June 2007
- 卷：39
- 期：4
- 页码：728-732
- 文件大小：194 K
摘要
The optical absorption of thermally evaporated copper phthalocyanine (CuPc) was studied in the UV-VIS-NIR region. The absorption spectra recorded in the UV-VIS region show two well-defined absorption bands of the phthalocyanine molecules, namely, the Soret (B) and the Q-band . The Q-band shows its characteristic splitting (Davydov splitting) of the main absorption peak in the metal phthalocyanine correlates with the relative tendencies of the metal to out-of-plane bonding. Some of the important spectral characteristics such as the molar extinction coefficient (εmolar), the oscillator strength (f), the electric dipole strength (q2) and absorption half-bandwidth (Δλ) of the principle optical transitions were evaluated. The analysis of the spectral behavior of the absorption coefficient b1; in the absorption region revealed two indirect allowed transitions with corresponding energies 2.95±0.03 and 1.55±0.02 eV.
The spectra of the infrared absorption allow characterization of vibration modes for the powder, as-deposited material and thin films of CuPc annealed at 423 K for two hours. Discussion of the obtained results and their comparison with the previous published data are also given.