十六氟酞菁鋅與酞菁鋅之超快載子動力學

Abstract

Phthalocyanines (Pc) are superior material, because it superior properties including ultrafast response, thermal and chemical stability, and flexible processing so that Pcs have been widely investigated for use in a various optoelectronic devices, such as thin film transistors. Pc dyes are two-dimensional aromatic molecules with an inner ring consisting of 18 π-electrons. In Pc molecules, various kinds of metal atoms can be coordinated to the center of rings and their chemical and electronic properties may be tuned through the choice of metal center. Standard Metallophthalocyanine (MPcs) are p-type organic semiconductor, and we can alter the molecular orbital structure drastically, and leading to n-type MPcs by addition of electron and remove the functional groups, particularly fluorine. Zinc Pc (ZnPc) and Hexadecafluorinated zinc (F16ZnPc) is an interesting material for photovoltaic and photoconductivity applications due to their high absorption coefficient in a wide spectral range of solar radiation and high energy conversion efficiency and photochemical stability. Using the absorption spectroscopy and femtosecond time-resolved pump-probe spectroscopy, we investigated the absorption properties and excited states relaxation dynamics attributed to the effects of morphology, including rod size and molecular interaction of ZnPc and F16ZnPc films. Transient differential transmittance signals show polarization dependence and excitation intensity dependence of the photoexcited ZnPc and F16ZnPc. The nano-structure of ZnPc and F16ZnPc show anisotripic relaxation of excitons for s- and p-polarized probe beams. We also employ ultrafast optical spectroscopy at different wavelengths to understand the inter-band decay in the excited state of F16ZnPc. The relaxation process is slower in the F16ZnPc than in the ZnPc due to the weak exciton coupling (longer stack distance) and steric obstruction created by the peripherally substituent (F-atoms) in F16ZnPc.

Phthalocyanines (Pc) are superior material, because it superior properties including ultrafast response, thermal and chemical stability, and flexible processing so that Pcs have been widely investigated for use in a various optoelectronic devices, such as thin film transistors. Pc dyes are two-dimensional aromatic molecules with an inner ring consisting of 18 π-electrons. In Pc molecules, various kinds of metal atoms can be coordinated to the center of rings and their chemical and electronic properties may be tuned through the choice of metal center. Standard Metallophthalocyanine (MPcs) are p-type organic semiconductor, and we can alter the molecular orbital structure drastically, and leading to n-type MPcs by addition of electron and remove the functional groups, particularly fluorine. Zinc Pc (ZnPc) and Hexadecafluorinated zinc (F16ZnPc) is an interesting material for photovoltaic and photoconductivity applications due to their high absorption coefficient in a wide spectral range of solar radiation and high energy conversion efficiency and photochemical stability. Using the absorption spectroscopy and femtosecond time-resolved pump-probe spectroscopy, we investigated the absorption properties and excited states relaxation dynamics attributed to the effects of morphology, including rod size and molecular interaction of ZnPc and F16ZnPc films. Transient differential transmittance signals show polarization dependence and excitation intensity dependence of the photoexcited ZnPc and F16ZnPc. The nano-structure of ZnPc and F16ZnPc show anisotripic relaxation of excitons for s- and p-polarized probe beams. We also employ ultrafast optical spectroscopy at different wavelengths to understand the inter-band decay in the excited state of F16ZnPc. The relaxation process is slower in the F16ZnPc than in the ZnPc due to the weak exciton coupling (longer stack distance) and steric obstruction created by the peripherally substituent (F-atoms) in F16ZnPc.