Preparation and Application of Organic-Inorganic Nanocomposite Materials in Stretched Organic Thin Film Transistors

High-transparency soluble polyimide with COOH and fluorine functional groups and TiO₂-SiO₂ composite inorganic nanoparticles with high dielectric constants were synthesized in this study. The polyimide and inorganic composite nanoparticles were further applied in the preparation of organic-inorganic hybrid high dielectric materials as the gate dielectric for a stretchable transistor. The optimal ratio of organic and inorganic components in the hybrid films was investigated. In addition, Jeffamine D2000 and polyurethane were added to the gate dielectric to improve the tensile properties of the organic thin film transistor (OTFT) device. PffBT4T-2OD was used as the semiconductor layer material and indium gallium liquid alloy as the upper electrode. Electrical property analysis demonstrated that the mobility could reach 0.242 cm²·V⁻¹·s⁻¹ at an inorganic content of 30 wt.%, and the switching current ratio was 9.04 × 10³. After Jeffamine D2000 and polyurethane additives were added, the mobility and switching current could be increased to 0.817 cm²·V⁻¹·s⁻¹ and 4.27 × 10⁵ for Jeffamine D2000 and 0.562 cm²·V⁻¹·s⁻¹ and 2.04 × 10⁵ for polyurethane, respectively. Additives also improved the respective mechanical properties. The stretching test indicated that the addition of polyurethane allowed the OTFT device to be stretched to 50%, and the electrical properties could be maintained after stretching 150 cycles.

Optically Isotropic, Colorless, and Flexible PITEs/TiO2 and ZrO2 Hybrid Films with Tunable Refractive Index, Abbe Number, and Memory Properties

A series of novel polyimidothioethers (PITEs) and the respective polymer hybrids of titania or zirconia with fantastic thermal stability and optical properties have been successfully prepared. These colorless PITEs with high transparency were synthesized by Michael polyaddition from commercially available dithiol and bismaleimides monomers. The PITE with sulfide and hydroxyl groups (S-OH) and the corresponding hybrid films declare ultra-lowest birefringence value of 0.002 and tunable refractive index (1.65–1.81 for S-OH/titania and 1.65–1.80 for S-OH/zirconia), implying large potential to the optical applications in the future. Moreover, the S-OH/zirconia hybrid films exhibit higher Abbe’s number and optical transparency than those of S-OH/titania system because larger energy band gap of ZrO₂. Furthermore, by adding titania and zirconia as electron acceptor into S-OH system, the charge transfer complex can be facilitated and stabilized caused by the lower LUMO energy level of hybrid materials. Consequently, the devices of memory prepared from these polymer films of hybrid showed interesting and adjustable memory behavior from DRAM, SRAM, to WORM at various titania or zirconia contents with a large ON/OFF ratio (10⁸), denoting that the memory devices derived from these highly transparent novel S-OH/TiO₂ and S-OH/ZrO₂ hybrid films are attractive for the electrical applications.

Highly transparent and flexible bio-based polyimide/TiO2 and ZrO2 hybrid films with tunable refractive index, Abbe number, and memory properties

The novel bio-based polyimide (4ATA-PI) and the corresponding PI hybrids of TiO2 or ZrO2 with excellent optical properties and thermal stability have been prepared successfully. The highly transparent 4ATA-PI containing carboxylic acid groups in the backbone could provide reaction sites for organic-inorganic bonding to obtain homogeneous hybrid films. These PI hybrid films showed a tunable refractive index (1.60-1.81 for 4ATA-PI/TiO2 and 1.60-1.80 for 4ATA-PI/ZrO2), and the 4ATA-PI/ZrO2 hybrid films revealed a higher optical transparency and Abbe's number than those of the 4ATA-PI/TiO2 system due to a larger band gap of ZrO2. By introducing TiO2 and ZrO2 as the electron acceptor into the 4ATA-PI system, the hybrid materials have a lower LUMO energy level which could facilitate and stabilize the charge transfer complex. Therefore, memory devices derived from these PI hybrid films exhibited tunable memory properties from DRAM, SRAM, to WORM with a different TiO2 or ZrO2 content from 0 wt% to 50 wt% with a high ON/OFF ratio (10(8)). In addition, the different energy levels of TiO2 and ZrO2 revealed specifically unique memory characteristics, implying the potential application of the prepared 4ATA-PI/TiO2 and 4ATA-PI/ZrO2 hybrid films in highly transparent memory devices.

Zinc and linkage effects of novel porphyrin-containing polyimides on resistor memory behaviors

The retention time of resistor type memory devices could be tuned by the linkage groups between porphyrin moiety and DSDA on the PIs. Moreover, the metal zinc also plays an important role in further tuning the memory behavior.

A novel porphyrin-containing polyimide for memory devices

A novel porphyrin-based polyimide ZnPor-t-DSDA was synthesized for memory applications and exhibits symmetric biswitching characteristic with a short retention time due to the coplanar structure between donor and acceptor units.

Organic Electronic Memory Devices

With the rapid development of the electronics industry in recent years, information technology devices, such as personal computers, mobile phones, digital cameras and media players, have become an essential part of our daily life. From both the technological and economic points of view, the development of novel information storage materials and devices has become an emergent issue facing the electronics industry. Due to the advantages of good scalability, flexibility, low cost, ease of processing, 3D-stacking capability and high capacity for data storage, organic-based electrical memory devices have been promising alternatives or supplementary devices to conventional inorganic semiconductor-based memory technology. The basic concepts and historical development of electronic memory devices are first presented. The following section introduces the structures and switching mechanisms of organic electronic memory devices classified as transistors, capacitors and resistors. Subsequently, the progress in the field of organic-based memory materials and devices is systematically summarized and discussed. Finally, the challenges posed to the development of novel organic electronic memory devices are summarized.

The influence of conformational parameters on some physical properties of polyimides containing naphthalene units

Conformational parameters of some aromatic polyimides–containing naphthalene units have been calculated by Monte Carlo method taking into consideration the hindered rotation produced by voluminous naphthalene units. Several physical properties such as solubility, glass transition temperature ( Tg), and initial decomposition temperature ( Td) have been studied with regard to the rigidity of the chain of these polyimides. It has been shown that Tg is well correlated with chain rigidity and with free volume ( Vfr) of the polymers, while the Td is not influenced by conformational parameters.

Side-chain and linkage-mediated effects of anthraquinone moieties on ambipolar poly(triphenylamine)-based volatile polymeric memory devices

Two ambipolar and thermally stable poly(triphenylamine)s with pendent anthraquinone acceptors were readily synthesized and prepared for the investigation of side-chain and linkage-mediated effects on the memory behaviour.