The resistive switching of polymer films embedded with nanoparticles (NPs) has recently attracted great attention for the promising application in next-generation memory devices. In particular, the polymer/NP interface is believed to play a key role in affecting the electronic structure and charge transport of the nanocomposites films. Herein, interfacial effects on switching performance were studied by embedding different NPs so as to engineer the polymer/NP interface. An ON/OFF current ratio of >104 was observed in our device with the switching mechanism of charge trapping and detrapping. Using quantum-chemical calculations, we demonstrate that the interaction between polymer and NP can largely affect the electronic structure at the interface, resulting in different interfacial barrier. The transmission spectrum shows that the charge transport between polymer and NP may depend on the relative energetic position of the frontier molecular orbitals with respect to the Fermi level under the effects of bias. Our study may provide useful information for understanding the underlying physics of polymer memory devices.

The resistive switching of polymer films embedded with nanoparticles (NPs) has attracted great attention for the promising application in flexible memory devices. However, the polymer/NP interface, which is believed to play a key role in the switching performance, makes its elucidation a vital issue. Herein, poly­(N-vinylcarbazole) thin films embedded with TiO2 NPs were spin-coated on flexible substrate to investigate how the polymer/NP interface affects the resistive switching, in particular, under bending conditions. The switching properties were found to depend on the degree of bending as well as the concentration of NPs, with the former bringing a strong influence on carrier transport. Using quantum-chemical calculations and finite-element analyses, we demonstrate that the micro cracks at polymer/NPs interfaces act as blocking layers that hinder the charge trapping and detrapping processes. Our study may provide useful information for understanding the underlying physics of polymer nanocomposite memory devices for the application to future flexible electronics.

No abstract

Polymer–nanoparticle (NP) hybrid nanocomposites act as essential elements for ultraflexible memory devices due to their processability, flexibility, and chemical resistance. However, a key limitation to their potential is associated with their mechanical reliability with the variation of temperature, which is still poorly understood. Herein, we systematically investigated the temperature-dependent fatigue failure of the Al/poly­(9,9-dioctylfluorene-alt-benzothiadiazole)–ZnO/Al/PET device, in which an 80% reduction in the fatigue lifetime of the device was observed as the temperature decreased from 40 to −40 °C. The finite element analysis results and theoretical calculations indicated that polymer/NP interfaces play different roles in crack propagations at different temperatures. At relatively high temperature, the elastic mismatch at the polymer/NP interface allows it to alleviate the crack propagation encountered with repetitive mechanical stress. However, this behavior is suppressed by the significant decrease of the polymer critical strain induced by the segmental motion in the polymer backbone at low temperature. In this case, large stiffness mismatch at the polymer/NP interface accelerates the crack propagation, which will inhibit electron transfer and eventually lead to device breakdown. This study may pave the way for future realization of ultraflexible hybrid memory devices utilized in harsh environments.

No abstract

In textile techniques, woven, knitted, non-woven and braiding techniques all can be used to weave tubular fabrics as intraluminal stents. The radial force is the most basic mechanical property of intraluminal stent. In this study, the influence of braiding parameters such as braided materials, diameter of stents and gear ratio on the radial compressive property of braided stents were studied.

No abstract