Optimal composition of the poly(triarylamine)-based polymer composite to maximize photorefractive performance

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.