TPD doped polystyrene as charge transporter in DiPBI sensitized photorefractive composites

We incorporate a mixture of polystyrene (PS) and the highly conductive N,N′-diphenyl-N,N′-bis(3-methylphenyl)-[1,1′-biphenyl]4,4′-diamine (TPD) as charge transporting agent into a photorefractive composite, wherein the liquid crystal 4-cyano-4-n-pentylbiphenyl (5CB) is the electro-optical unit and the perylene bisimide dimer DiPBI acts as sensitizing component. Investigation of the photocurrent reveals a strong enhancement of the photoconductivity. Compared to composites, wherein poly-n-vinylcarbazole (PVK) is the charge transporting agent, the internal photocurrent efficiency is enhanced 11 times. This dramatic improvement is attributed to an increase of charge generation and transport and it allows for a reduction of the applied electric field to get a photoconductivity that is comparable to PVK comprising composites. © 2012 Optical Society of America OCIS codes: (160.5320) Photorefractive materials; (160.4890) Organic materials; (050.7330) Volume gratings. References and links 1. 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