Chain flexibility effect on the refractive index grating of fully functionalized carbazole/DO3/epoxy polymer

Abstract

The photorefractive (PR), photoconductive, and holographic characteristics of 3-amino-9-ethyl carbazole (AEC)/dispersed orange 3 (DO3)/diepoxy main chain copolymers are investigated to study the relationship between the structure and properties. The recorded pattern exhibits good fringe contrast with the resolution 20 m in the recorded hologram. The formation rate of refractive index grating (PR grating) can be speeded up by applying an electric field or changing comonomer structure or monomer composition. Faster PR response can be achieved by incorporating aliphatic diepoxy with longer chain length or increasing the concentration of the charge transport moieties, while more nonlinear optical (NLO) segment (DO3) in the copolymer results in higher diffraction efficiency. The dark decay rate of the PR film at room temperature depends on the dark conductivity and steric interaction between the NLO chromophores and the polymer matrix. However, the latter shows greater influence on the dark decay at elevated temperature. More charge transport segment increases the dark conductivity and it leads to higher dark decay rate. The diffracted signals of polymers synthesized from the diepoxy comonomers containing longer soft chain exhibit slower dark decay at room temperature, but drop sharply as the temperature get higher. In comparison with experimentally measured dark decay at elevated temperature, thermal stimulated current spectroscopy is a more sensitive tool than differential scanning calorimetry diagrams to evaluate what temperature a sharp dark decay of the PR signal will occur.

Fabrications and Applications of Stimulus-Responsive Polymer Films and Patterns on Surfaces: A Review

“…The dark decay of the PR properties at elevated temperature can also be evaluated by the thermally-stimulated discharge current spectroscopy technique. The recorded pattern exhibits good fringe contrast, with a resolution of 20 μm in the recorded hologram [ 86 ]. The formation rate of the refractive index grating (PR grating) can be accelerated by applying an electric field or changing the comonomer structure or monomer composition.…”

Organic Photorefractives: Mechanisms, Materials, and Applications

“…This material exhibited a 2BC gain coefficient of only 2.3 cm -1 . Since then, much progress has been made in the development of high-performance fully functionalized PR materials. ,,,,,,− A recent review of strategies of material design applied to the synthesis of fully functionalized polymers can be found in ref . Here we summarize the performance of the best fully functionalized polymers reported to date.…”

“…Since then, much progress has been made in the development of high-performance fully functionalized PR materials. 25,153,154,168,216,217,[254][255][256][257] A recent review of strategies of material design applied to the synthesis of fully functionalized polymers can be found in ref 25. Here we summarize the performance of the best fully functionalized polymers reported to date. Net gain coefficients of over ∼200 cm -1 at zero external electric field at 690 nm were obtained in high T g prepoled conjugated polymers containing Ru photogenerator complexes, introduced into the polymer backbone (Ru-FFP, Figure 17a, Table 2).…”