Updatable colorful display of vector hologram in azo–poly(9‐vinylcarbazole)–TiO 2 nanocomposite films

Organic optoelectronic copolymer involving PVK and F8T2: Synthesis and characterization

The synthesis of new fluorescent polymers based on π-conjugated chains is a major challenge for organic electronic. The materials must be soluble, stable over long periods and able to be produced with a high yield. In particular, poly (vinylcarbazole), poly (fluorenes), and poly (thiophene) partially meet these criteria. In this study, new soluble copolymers PVK-F8T2 was synthesized from poly(9-vinylcarbazole) (PVK) and poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(bithiophène)] (F8T2). As these materials are highly luminescent and green-emitting, they have good chemical and thermal stability and can be easily functionalized. Here, the vibrational and optical properties of PVK-F8T2 was studied using several different techniques, including Infrared absorption, Raman scattering, thermogravimetric analysis (TGA), UV-visible optical absorption, and both stationary and transient photoluminescence. The novel copolymer shows an increase of thermal stability compared to the two original polymers (PVK and F8T2). The stationary and transient photoluminescence reveal an energy transfer from PVK to F8T2. This study indicates that these copolymers are good candidates for photophysical applications.

Enhancing hologram memory via deposition of plasmonic nanocubes on orderly mesoporous titania

Hologram is regarded as a key platform for large-volume data storage and information encryption. Diversity of plasmonic nanostructures makes it being a kind of vibrant hologram memory media. However, recording of amplitude, phase and polarization of light is restricted by difficulty to obtain anisotropic morphology of metal particles. Photocatalysis approach allows wide size distribution of Ag plasmonic nanoparticles after a long growth time on titania but suffers from the disadvantage that the shape of plasmonic nanostructures is mostly isotropic, which weakens optical vector sensitivity and information stability. Herein, Ag nanocubes exhibiting high polarization response ability are deposited on orderly mesoporous titania via UV photocatalysis. Recording efficiency of hologram by orthogonally linearly polarized lights is enhanced and the memorized information can be resistant to UV-erasure, both benefiting from the distal resonance of Ag nanocubes. This work delivers a guideline for long-term data storage and high-efficiency display devices.