Big Third-order Nonlinear Optical Properties of Two Poly[(3-alkylthiophene-2, 5-diyl)-(benzylidenequinomethane-2, 5-diyl)] Derivatives  

作　　者：GAOChao WUHong-cai YIWen-hui LIBao-ming SUNJian-ping MENGLing-jie 

机构地区：[1]Schoolofelectron,andInform.Eng.,Xi＇anJiaotongUniversity,Xi＇an710049,CHN [2]Schoolofelectron,andInform.Eng.,Xi＇anJiaotongUniversity,Xi＇an710049,CHN

出　　处：《Semiconductor Photonics and Technology》2005年第2期99-102,共4页半导体光子学与技术（英文版）

基　　金：National Natural Science Foundation of China (60277002)

摘　　要：Two novel poly[(3-alkylthiophene-2,5-diyl)-(benzylidenequinomethane-2,5-diyl)s] derivatives, poly[ (3-butylthiophene-2,5-diyl)-( p-N,N-dimethylamino) benzylidenequinomethane-2,5-diyl) ] ( PBTDMABQ) and poly [( 3-octylthiophene2,5-diyl) -(p-N, N-dimethylamino ) benzylidenequinomethane-2, 5-diyl)] (POTDMABQ), were synthesized.The band gaps of the two polymers are calculated as 1. 75 eV for PBTDMABQ and 1. 69 eV for POTDMABQ,respectively. The homogenous films of the two polymers were prepared and their third-ordernonlinear optical properties were studied by the backward degenerate four-wave mixing at 532 nm. Byusing the relative measurement technique, the third-order nonlinear optical susceptibilities ofPBTDMABQ and POTDMABQ are calculated as 5. 62 X 10^(-9) and 1. 22 X 10^(-8) ESU, respectively. It isfound that substituted alky groups have strong effects on the band gap and nonlinear opticalproperties of the two polymers. The relatively big third-order nonlinear optical susceptibilitiesand small band gap of POTDMABQ resulted mainly from the longer alkyl with strong electron-donatingability can enhance the delocation degree of conjugated π electronics.Two novel poly[（3-alkylthiophene-2,5-diyl）- （benzylidenequinomethane-2,5-diyl）s] derivatives, poly[（3-butylthiophene-2,5-diyl）-（p-N,N-dimethylamino）benzylidenequinomethane-2,5-diyl)]（PBTDMABQ） and poly[（3-octylthiophene2,5-diyl） -（p-N,N-dimethylamino）benzylidenequinomethane-2,5-diyl)]（POTDMABQ）, were synthesized. The band gaps of the two polymers are calculated as 1.75eV for PBTDMABQ and 1.69eV for POTDMABQ, respectively. The homogenous films of the two polymers were prepared and their third-order nonlinear optical properties were studied by the backward degenerate four-wave mixing at 532nm. By using the relative measurement technique, the third-order nonlinear optical susceptibilities of PBTDMABQ and POTDMABQ are calculated as 5.62×10-9 and 1.22×10-8ESU, respectively. It is found that substituted alky groups have strong effects on the band gap and nonlinear optical properties of the two polymers. The relatively big third-order nonlinear optical susceptibilities and small band gap of POTDMABQ resulted mainly from the longer alkyl with strong electron-donating ability can enhance the delocation degree of conjugated π electronics.

关 键 词：poly [( 3-alkylthiophene)-( benzylidenequinomethane)] derivatives degeneratefour-wave mixing third-order nonlinear susceptibility band gap 

分 类 号：TN304.52[电子电信—物理电子学]