金屬(鈦,鋅)酞菁之超快載子動力學及非線性光學特性研究

Abstract

Phthalocyanines (Pcs) have strong pi-conjugate carrier transitions resulting from their unique π-staking structure. Many researches show that Pcs tend to have one dimensional charge diffusion and this is possible because energy transfer along π-staking direction is much faster than that along planner direction of molecules. Carrier dynamics of excitation and relaxation can reflect the anisotropy in molecular energy transfer, but relatively little has been known for Pcs. We measured optical polarization dependent carrier dynamics of a metallated Pc, TiOPc, and systematically studied the anisotropic carrier transfer mechanism. Carrier relaxation time of optical beam with the polarization parallel to the π-staking direction of TiOPc film is found obviously faster than that of optical beam with perpendicular polarization. Pc is also well known for its high nonlinearity, which makes it known for an excellent material as optical limiter as well as all-optical-switching. The nonlinear absorption coeffienct near the band tail of Q-band (800-860nm) of another metallic Pc, ZnPC was measured by using standard Z-scan technique.

Phthalocyanines (Pcs) have strong pi-conjugate carrier transitions resulting from their unique π-staking structure. Many researches show that Pcs tend to have one dimensional charge diffusion and this is possible because energy transfer along π-staking direction is much faster than that along planner direction of molecules. Carrier dynamics of excitation and relaxation can reflect the anisotropy in molecular energy transfer, but relatively little has been known for Pcs. We measured optical polarization dependent carrier dynamics of a metallated Pc, TiOPc, and systematically studied the anisotropic carrier transfer mechanism. Carrier relaxation time of optical beam with the polarization parallel to the π-staking direction of TiOPc film is found obviously faster than that of optical beam with perpendicular polarization. Pc is also well known for its high nonlinearity, which makes it known for an excellent material as optical limiter as well as all-optical-switching. The nonlinear absorption coeffienct near the band tail of Q-band (800-860nm) of another metallic Pc, ZnPC was measured by using standard Z-scan technique.