Copolymer dielectrics with balanced chain-packing density and surface polarity for high-performance flexible organic electronics

Abstract

The ever-increasing demand for flexible electronics calls for the development of low-voltage and high-mobility organic thin-film transistors (OTFTs) that can be integrated into emerging display and labeling technologies. Polymer dielectrics with comprehensive and balanced dielectric properties (i.e., a good balance between their insulating characteristics and compatibility with organic semiconductors) are considered particularly important for this end. Here, we introduce a simple but highly efficient strategy to realize this target by using a new type of copolymer as dielectrics. Benefiting from both high chain packing density guaranteeing dielectric properties and surface polarity optimizing molecular packing of organic semiconductors, this rationally designed copolymer dielectric endows flexible OTFTs with high mobility (5.6 cm2 V−1 s−1), low operating voltage (3 V) and outstanding stability. Further, their applicability in integrated circuits is verified. The excellent device performance shows exciting prospects of this molecular-scale engineered copolymer for the realization of plastic high-performance integrated electronics.

A Facile Method for the Growth of Organic Semiconductor Single Crystal Arrays on Polymer Dielectric toward Flexible Field‐Effect Transistors

“…These polar components can enhance the surface polarity, contributing to much stronger polarity of treated PVP surface compared to the untreated surface. In addition, the existence of these polar components can also result in an increase of the surface energy . To verify this, we compare the surface energies of the treated PVP with untreated PVP by detecting their contact angles with water and diiodomethane (Figures S2 and S4, Supporting Information).…”

“…Flexible gate dielectrics play an important role in determining the device performance as well as bending stability of flexible organic field‐effect transistors (OFETs) . In comparison with conventional inorganic dielectrics, polymer dielectrics with intrinsic mechanical flexibility are considered to be a key component of flexible OFETs . To date, various polymer dielectrics, such as polyimide (PI), poly(4‐vinylphenol) (PVP), and polystyrene (PS), etc., have been widely used for the construction of flexible OFETs .…”

“…Besides the polymer dielectrics, high‐quality organic semiconductor layers are very crucial to gain a high device performance for the flexible OFETs. Recently, much attention has been devoted to improve the crystallinity and molecular packing uniformity of organic semiconductors on polymer dielectrics . For instance, Fuchs and co‐workers reported that PI substrate with many strong polar groups (COOH/CONH) could induce long‐range ordered arrangement of organic molecules on its surface for the formation of high‐quality crystalline films with large crystal domain size .…”

“…Recently, much attention has been devoted to improve the crystallinity and molecular packing uniformity of organic semiconductors on polymer dielectrics . For instance, Fuchs and co‐workers reported that PI substrate with many strong polar groups (COOH/CONH) could induce long‐range ordered arrangement of organic molecules on its surface for the formation of high‐quality crystalline films with large crystal domain size . Hu and co‐workers also demonstrated that self‐structured nanogrooves of poly(amic acid) (PAA) and the strong surface polarity collaboratively allowed more ordered molecular packing of organic semiconductors, giving rise to an enhanced film crystallinity and a larger domain size .…”

Understanding, Optimizing, and Utilizing Nonideal Transistors Based on Organic or Organic Hybrid Semiconductors

“…The resulting OFETs exhibited excellent performance (Figure f) with a skyrocketing mobility reaching 30.6 cm 2 V −1 s −1 . Using a similar polymeric dielectric, the strategy has further led to OFETs with high mobility (5.6 cm 2 V −1 s −1 ), low operating voltage (3 V), and outstanding stability …”