Heterogeneous Functional Dielectric Patterns for Charge-Carrier Modulation in Ultraflexible Organic Integrated Circuits.

Flexible electronics have gained considerable attention for application in wearable devices. Organic transistors are potential candidates to develop flexible integrated circuits (ICs). A primary technique for maximizing their reliability, gain, and operation speed is the modulation of charge-carrier behavior in the respective transistors fabricated on the same substrate. In this work, heterogeneous functional dielectric patterns (HFDP) of ultrathin polymer gate dielectrics of poly((±)endo,exo-bicyclo[2.2.1]hept-ene-2,3-dicarboxylic acid, diphenylester) (PNDPE) are introduced. The HFDP that are obtained via the photo-Fries rearrangement by ultraviolet radiation in the homogeneous PNDPE provide a functional area for charge-carrier modulation. This leads to programmable threshold voltage control over a wide range (-1.5 to +0.2 V) in the transistors with a high patterning resolution, at 2 V operational voltage. The transistors also exhibit high operational stability over 140 days and under the bias-stress duration of 1800 s. With the HFDP, the performance metrics of ICs, for example, the noise margin and gain of the zero-VGS load inverters and the oscillation frequency of ring oscillators are improved to 80%, 1200, and 2.5 kHz, respectively, which are the highest among the previously reported zero-VGS -based organic circuits. The HFDP can be applied to much complex and ultraflexible ICs.