Low-voltage-operating high-performance organic field-effect transistors (OFETs) are regarded as the building blocks of analog and digital integrated circuits for next-generation electronics. To fulfill this role, such an OFET must have high-k characteristics for increasing the capacitance values to make enough of a field effect charge, a hydrophobic surface that does not cause charge trapping, and a low leakage current property to guarantee operating stability. This study demonstrated a new strategy to induce high-k characteristics (> 8) in highly durable polysilsesquioxane (PSQ)-based dielectric materials. This strategy involved realizing a permanent dipolar side chain reorientation under an electric field and its applications to low-voltage-driving OFETs showing high field-effect mobility levels as high as 27 cm2 V-1 s-1. Different PSQs were characterized, and the differences in their characteristics led to distinct polarization phenomena, resulting in different hysteresis behaviors during device operation. We were also able to fabricate printed unit devices on flexible platforms and integrated devices based on OFETs through these materials, and showed robust switching or memory performances under low-voltage-operation conditions. Therefore, this facile but powerful synthesis strategy for high-k PSQ dielectrics can pave a new path for the production of practical printable high-k dielectrics for organic electronics and hence realize next-generation integrated electronics. 

[Reference] Heqing Ye, Hyeok-jin Kwon, Su Cheol Shin, Hwi-young Lee, Young Ho Park, Xiaowu Tang, Ruxian Wang, Kanghyuck Lee, Jisu Hong, Zhijun Li, Wonkyo Jeong, Jiyeong Kim, Chan Eon Park, Jihoon Lee,* Tae Kyu An,* Insik In,* and Se Hyun Kim, The Hidden Potential of Polysilsesquioxane for High-k: Analysis of the Origin of its Dielectric Nature and Practical Low-Voltage-Operating Applications beyond the Unit Device, Advanced Functional Materials, https://doi.org/10.1002/adfm.202104030

[Main Author] Jihoon Lee (Korea National University of Transportation), Tae Kyu An (Korea National University of Transportation), Insik In (Korea National University of Transportation), Se Hyun Kim (Yeungnam University)

* Contact : taekyu1985@ut.ac.kr