Enhancing the Toughness of Free-Standing Polyimide Films for Advanced Electronics Applications: A Study on the Impact of Film-Forming Processes

High-quality and free-standing polyimide (PI) film with desirable mechanical properties and uniformity is in high demand due to its widespread applications in highly precise flexible and chip-integrated sensors. In this study, a free-standing PI film with high toughness was successfully prepared using a diamine monomer with ether linkages. The prepared PI films exhibited significantly superior mechanical properties compared to PI films of the same molecular structure, which can be attributed to the systematic exploration of the film-forming process. The exploration of the film-forming process includes the curing procedures, film-forming substrates, and annealing treatments. Additionally, the thickness uniformity and surface homogeneity of free-standing films were crucial for toughness. Increasing the crystallinity of the PI films by eliminating residual stress also contributed to their high strength. The results demonstrate that by adjusting the above-mentioned factors, the prepared PI films possess excellent mechanical properties, with tensile strength and elongation at break of 194.71 MPa and 130.13%, respectively.

Recent Progress in Aromatic Polyimide Dielectrics for Organic Electronic Devices and Circuits

Polymeric dielectrics play a key role in the realization of flexible organic electronics, especially for the fabrication of scalable device arrays and integrated circuits. Among a wide variety of polymeric dielectric materials, aromatic polyimides (PIs) are flexible, lightweight, and strongly resistant to high-temperature processing and corrosive etchants and, therefore, have become promising candidates as gate dielectrics with good feasibility in manufacturing organic electronic devices. More significantly, the characteristics of PIs can be conveniently modulated by the design of their chemical structures. Herein, from the perspective of structure optimization and interface engineering, a brief overview of recent progress in PI-based dielectrics for organic electronic devices and circuits is provided. Also, an outlook of future research directions and challenges for polyimide dielectric materials is presented.

Direct Effect of Dielectric Surface Energy on Carrier Transport in Organic Field-Effect Transistors

The understanding of the characteristics of gate dielectric that leads to optimized carrier transport remains controversial, and the conventional studies applied organic semiconductor thin films, which introduces the effect of dielectric on the growth of the deposited semiconductor thin films and hence only can explore the indirect effects. Here, we introduce pregrown organic single crystals to eliminate the indirect effect (semiconductor growth) in the conventional studies and to undertake an investigation of the direct effect of dielectric on carrier transport. It is shown that the matching of the polar and dispersive components of surface energy between semiconductor and dielectric is favorable for higher mobility. This new empirical finding may show the direct relationship between dielectric and carrier transport for the optimized mobility of organic field-effect transistors and hence show a promising potential for the development of next-generation high-performance organic electronic devices.

Ultrathin annealing-free polymer layers: new opportunity to enhance mobility and stability of low-voltage thin-film organic transistors

We demonstrate an ultrathin annealing-free polymer layer with compact structure and perfect surface state which makes the application of ultra-thin devices and low-power consumption possible.