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Abstract An electron spin resonance (ESR) spectroscopy as well as a photoelectron yield spectroscopy (PYS) is used to study the photocarrier behavior (generation and transport) for photorefractivity in poly(N -vinyl carbazole) (PVCz) and poly[bis(2,4,6-trimethylphenyl)amine] (PTAA) based photorefractive (PR) polymer composites. ESR spectra directly catch the radical species in PR composites on the laser illumination under applied electric field; the cation radicals and anion radicals induced under light illumination upon applying an electric field were evaluated. PYS was used to evaluate the energy levels and the width of the electron density of states (DOS) of the carrier transport manifolds. The narrower DOS width of the PTAA-based PR composite was significantly related to the faster response time and broader DOS width for the PVCz-based PR composite to the slower response time. Based on all these results, the comprehensive energy diagrams, including perspectives on the energy level and its distribution, the generated charge carriers with spins, and occupied trap density, are proposed. Graphical abstract Image 10130 Highlights • Photorefractive dynamics are studied using ESR and PYS with common PR measurements. • Number of polymer cations, 2.4–3.1 × 1016 cm−3, was evaluated from ESR signal. • Mobility is 1.07 × 10−6 and 1.15 × 10−8 cm2 V−1 s−1 for respective PTAA and PVCz PR polymers. • Faster response is due to narrower DOS width with higher mobility for PTAA PR polymer. • Slower response is due to broader DOS width with lower mobility for PVCz PR polymer. [ABSTRACT FROM AUTHOR]

Seven C- methylcalix[4]resorcinarene (CRA)-based photorefractive (PR) hyper-structured molecular glasses (HSMGs) containing carbazole-based methine nonlinear optical (NLO) chromophores were designed and synthesized via esterification between carboxyl-containing asymmetric CRA core molecule and hydroxyl-containing functional compounds. When the feed ratio of hydroxyl-containing NLO functional compounds to carboxyl groups of CRA-COOH was kept at 1.5/1 by mole, the degree of introduction of NLO chromophore to the CRA core was above 70%. All the HSMGs show low glass transition temperatures ( T g ), and good solubility in common low boiling point solvents such as THF, CHCl 3 , etc . Powder XRD and UV–vis absorption in films of HSMGs indicate that the aggregation, packing and crystallization of the NLO chromophores in these HSMGs had been effectively reduced. Doping with N -ethyl-carbazole (ECz) as a plasticizer and [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) as a photosensitizer, all the HSMGs composites showed good PR effects. All the coupling gain coefficients ( Γ ) of HSMGs-based composites are about twice to the corresponding small molecular NLO chromophores-based composites, thanks to the decreased NLO chromophores antiparallel packing caused by the asymmetric CRA core. Among them, CRA-CSN/ECz/PCBM (69:30:1, wt%) composite exhibited the best performance with the Γ value of 78.2 cm −1 at the external electric field of 12.5 V μm −1 , which is one of the best performance in molecular glasses under the same test conditions. Coupled with their convenient synthesis, this work will provide a new simple design strategy for organic PR materials. [ABSTRACT FROM AUTHOR]