Effect Of Peripheral Substituent On The Ultra-fast Nonlinear Nonlinear Absorption Properties Of Pyrene Organic Molecules

Pyrene organic conjugated molecules have wide application potential in two-photon pumped fluorescence imaging,optical limiting,optical storage and other fields due to their diverse structures and high nonlinear polarizability.The study of the correlation between the microstructure and the macroscopic physical properties of pyrene organic conjugated molecules is not only helpful for the study of the nonlinear optical mechanism of organic molecules,but also of guiding significance for the research and development of nonlinear optical materials in the future.Two pyrene derivatives with different substituents 1-(pyren-1-yl)-3-(5-Chlorothiophene-2-yl)acrylic ketone(1612)and 1-(pyren-1-yl)-3-(5-Phenylthiophene-2-yl)acrylic ketone(1613)were synthesized.The nonlinear absorption properties of two pyrene organic molecules were studied by femtosecond z-scan measurement technology,and it was found that the nonlinear optical absorption response of 1613 was stronger than that of 1612 in 515nm and 532nm.The results of quantum chemistry calculation show that the nonlinear absorption change is related to the benzene peripheral substituents.he results of quantum chemical calculations show that the addition of benzene increases the conjugate plane length of pyrene derivatives thereby enhancing the nonlinear absorption properties of the material.The results of femtosecond transient absorption spectra show that the nonlinear absorption mechanism of the two molecules is excited absorption.The transient excited state absorption curve shows that 1613 has a longer excited state lifetime.The results of quantum chemical calculations show that the addition of benzene increases the conjugate plane length of pyrene derivatives thereby enhancing the nonlinear absorption properties of the material.The results of this paper reveal the mechanism of the influence of peripheral substituents on the nonlinear absorption and ultra-fast relaxation of pyrene organic conjugated molecules.It can provide reference for the future development of optoelectronic materials based on pyrene molecules.