Investigations on the grating dynamics in a fast photorefractive guest–host polymer

Organic Photorefractive Materials and Applications

“…. Chemical structures of hole-conductors employed in photo refractive materials: 1 PVK, [ 62 ] 2 PCzEA, [ 63 ] 3a PVI, [ 60 ] 3b PVDMI, [ 60 ] 4 DBOP, [ 64 ] 5a PSX-Cz, [ 65 ] 5b PSX-bTPA, [ 66 ] 5c PSX-IDEH, [ 67 ] 5d PSX-PhPA, [ 67 ] 6 TFB, [ 68 ] 7 PF6-TPD, [47,54,55,69] 8 TPD-PPV, [70,71] 9 PDAS, [ 72 ] 10 MM-PSX-TAA, [ 73 ] 11 TPDac, [ 74 ] 12 PATPD, [75,76] 13 MDCETPD, [ 77 ] 14 p-PMEH-PPV, [ 78 ] 15 EhCzThThZ, [ 79 ] 16 DiCz. times in the order of seconds under 830 nm illumination and 57 V μ m − 1 .…”

“…A fl uorenetriarylamine-copolymer (TFB 6 ) as PR host was demonstrated in. [ 68 ] Also, bi-functional charge-transport/chromophore molecules based on TPD were demonstrated (MDCETPD 13 . [ 77 ] ) The nematic-like mesophase photoconductive polymer PPT-TPA, which features triarylamine side-groups attached to an aromatic rigid backbone was introduced by Kwon et al [ 97 ] Generally, TPD-based materials are known to exhibit higher charge-carrier mobilities and lower ionization potentials relative to carbazole-based materials.…”

Materials Design and Physics of Organic Photorefractive Systems

“…[31,32] Moreover, only tentative theoretical descriptions are available. [33,34] Thus, different analytical functions are used, ranging from single- [35] and doubleexponential, [31,32,36] and to stretched exponential [37] fits. This is often motivated by assuming that the first time constant t 1 describes the build-up of the space-charge field, whereas at later times chromophore reorientation and other effects dominate.…”

“…In many cases, one must also introduce a cut-off at longer time scales, on which the fits deviate significantly from the experimental results. [31,32] Recent work [32] uses an inverse Laplace transform which does not require any a priori assumptions about the number of processes (such as exponential fits) involved in the grating formation, since the algorithm performs the fit with the smallest possible number of free parameters. Therefore, the inverse Laplace transform analysis might yield new insight into the dynamics of grating formation.…”

“…Five typical photoconducting polymers used as host material for photorefractive systems: PVK, PSX, DBOP-PPV, [50] TPDac polymer, [49] and TFB. [32] agent such as the PVK-monomer ECZ was required to lower the T g to room temperature. This allows for both orientational enhancement of the refractive index modulation and in situ poling of the chromophores by the applied electric field.…”