TRIPHENYLAMINE-BASED PHOTOCONDUCTIVE POLYMERS: TOWARD VIDEO RATE RESPONSE PHOTOREFRACTIVE DEVICE

摘要

Two kinds of triphenylamine (TPA)-based polymer are introduced and applied to photorefractive (PR) composite. A polymer which is poly(4-(diphenylamino)benzyl acrylate) (PDAA) have TPA moiety attached to acrylate main chain. Another which is poly(4-((4-methoxyphenyl)(phenyl)amino)benzyl acrylate) (PMPAA) uses TPA derivative which has been modified with a methoxy group at para- position. A nonlinear optical (NLO) chromophore of 2-(4-(azepan-1-yl)benzylidene)malononitrile (7DCST) is used. Phenyl-C61-butyric acid methyl ester (PCBM) is a sensitizer. TPA-based plasticizer which is (4-(diphenylamino)phenyl)methanol (TPAOH) is added to reduce the glass transition temperature and maintain hole mobility. The composite's ability for chromophore orientation has been significantly improved by using PMPAA polymer. The plasticizer of TPAOH can act as an effective trap in the composite based on PDAA polymer. High diffraction efficiency (up to 70%) with a fast time constant of 25 ms can be obtained in PDAA-based composite.