Synthesis Of Novel Organic Second Order Nonlinear Optical Chromophores

With the rapid development of information technology in the 21st century,higher and higher requirements have been put forward for the transmission speed,storage and processing of information.In the past,the traditional microelectronic integrated circuit prevailed,but due to its relatively low transmission efficiency,as well as poor heat dissipation and other problems,it has been unable to achieve the purpose of large capacity,high speed data transmission.With the rise of photonics and the increasing desire for high-speed data transmission,optical communication with light wave as carrier has been gradually developed.The rapid development of optical communication is due to the unique advantages of photon-based materials in bandwidth,transmission speed,parallelism,high density and anti-electromagnetic interference.The key to the application of optoelectronic communication technology is the preparation of excellent electro-optic materials.In this paper,the organic second-order nonlinear optical(NLO)chromophores are designed,and a new strategy is adopted in the donor part of the chromophores to synthesize the new organic second-order nonlinear optical chromophores,and the organic electro-optic materials with high electro-optic coefficient are obtained.The main work contents of this paper are summarized as the following two points:1.Two novel chromophores B-C were designed and synthesized by using thiophene derivatives as donors,combining with thiophene electronic bridge and tricyanovinyldihydrofuran(TCF)receptor.The donors were 5-(methyl(phenyl)amino)thiophene and 5-(bis(4-methoxyphenyl)amino)thiophene.In addition,in order to compare their properties,chromophore A with diethylaminophenyl as donor,thiophene electron bridge and TCF receptor was synthesized for comparison.Compared with chromophore A,the maximum UV absorption wavelength(?_max)of chromophore B is almost the same as that of chromophore A,while the?_max of chromophore C has obvious red shift.Although the first hyperpolarizability of chromophore B is close to that of chromophore A,the first hyperpolarizability of chromophore C containing 5-(bis(4-methoxyphenyl)amino)thiophene donor is about 63%higher than that of chromophore A.In addition,the electro-optic coefficient(r₃₃)of chromophore B is about 18%higher than that of chromophore A,and the electro-optic coefficient(r₃₃)of chromophore C is about 95%higher than that of chromophore A.This indicates that the performance of chromophores B-C containing(arylamino)thiophene donor are better than that of chromophore A containing aniline donor,especially the performance of chromophore C is excellent.2.Three novel chromophores B-D have been synthesized based on thiophene derivatived donors,including5-(methyl(phenyl)amino)thiophene5-(bis(4-methoxyphenyl)amino)thiophene 5-((4-methoxyphenyl)(methyl)amino)thiophene groups respectively,with the same isophorone-derived bridge and tricyanovinyldihydrofuran(TCF)acceptors.A new strategy was proposed to improve the electron donating ability of the chromophore,thienyl groups were explored as a replacement for the phenyl unit in the donor part of the chromophore.Density functional theory calculations suggested that the first hyperpolarizability of(arylamino)thiophene donor-containing chromophore B-D is about 20%higher than that of 4-(dialkylamino)phenyl counterpart chromophore A.At least 50%enhancement in bulk nonlinearity(r₃₃)is realized as the donor subunits were changed from alkylaniline to(arylamino)thiophene donors.Polymeric thin films doped with 25 wt%chromophore B-D have been poled to afford large r₃₃ values of 131,143 and 138 pm/V at 1.31?m,respectively,which is much higher than the EO activity of chromophore A(88 pm/V).