Photorefractive (PR) and photoconductive properties of methyl-substituted poly(triarylamine) (PTAA) based PR composite is presented. PR composite consisted of PTAA, piperidinodicyanostyrene, (2,4,6-trimethylphenyl)diphenylamine, and [6,6]-phenyl-C61-butyric acid methyl ester. Photocurrent is simultaneously measured when a transient degenerate four wave mixing is recorded. Diffraction efficiency of 16.6%, response time of 5 ms, and sensitivity of 43 cm 2 J 21 are measured under an applied field of 45 V lm 21 and 632.8 nm illumination with the intensity of 1.5 W cm 22 . Response time of 10.2 ms with diffraction efficiency of 47.0% is obtained under a same field and 532 nm illumination with the intensity of 0.427 W cm 22 . Higher diffraction and faster response is due to the large photocurrent in the order of hundreds lA measured. The resultant trap density is in the order of 10 14 cm 23 . Thus, spacecharge field less than 1 V lm 21 is evaluated, which limits the PR response.

The photorefractive (PR) response and dynamics are investigated in a methyl-substituted poly(triarylamine) (PTAA)-based PR composite. The charge transfer complex between PTAA and an added small amount of second acceptor, (tris(8-hydroxyquinolinato)aluminium) Alq(3), effectively suppresses the photoconductivity, and thus the sample is able to withstand the dielectric breakdown at a high electric field. The resulting PR response is enhanced at a higher electric field. Sub-millisecond PR response times were observed for both optical diffraction and optical amplification: i.e., 350 μs for optical amplification and 860 μs for optical diffraction observed under 532 nm illumination (0.534 W cm(-2)) at 60 V μm(-1). The response time of optical amplification followed the photocurrent response time of 367 μs.

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A holographic display system requires the external diffraction efficiency to be greater than 10% and four orders of magnitude of sensitivity for practical usage. To achieve such requirements, the photorefractive (PR) performance of PR composite based on poly[bis(2,4,6-trimethylpheneyl)amine] (PTAA) has been investigated. In the present report, the change of the content of PTAA as a photoconductive polymer, (2,4,6-trimethylphenyl)diphenylamine (TAA) as a photoconductive plasticizer, and second trap agent bathophenanthroline (BPhen) reasonably optimized the PR response time and external diffraction efficiency. High sensitivity of 1851 cm2 J−1 with response time of 494 μs and external diffraction efficiency of 23.9% were achieved at 532 nm and 60 V μm−1 by reducing the content of PTAA and increasing the contents of TAA and BPhen. Decreasing the amount of PTAA and increasing the contents of TAA and BPhen lowered the absorption coefficient, resulting in the high external diffraction efficiency. The narrower distribution of the electronic density of states (DOS) for PTAA/TAA (43.5/20 and 33.5/30) also contributed to the shorter PR response time of hundreds of microseconds.

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