High Performance Flexible Transistors With Polyelectrolyte/Polymer Bilayer Dielectric
Sachin Rahi, Vivek Raghuwanshi, Pulkit Saxena, Gargi Konwar, Shree Prakash Tiwari
Abstract
Flexible organic field-effect transistors (OFETs) consisting of polyvinyl alcohol (PVA)/ polyelectrolyte polyacrylic acid (PAA) bilayer gate dielectric are demonstrated. These devices exhibited maximum field-effect mobility of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu _{\text {max}} ~\sim {0.94}$ </tex-math></inline-formula> cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{{2}}\cdot \text{V}^{-{1}}\cdot \text{s}^{-{1}}$ </tex-math></inline-formula> with an average of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu _{\text {avg}} ~\sim {0.7}$ </tex-math></inline-formula> (±0.1) cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{{2}}\cdot \text{V}^{-{1}}\cdot \text{s}^{-{1}}$ </tex-math></inline-formula> in the saturation regime and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{ \mathrm{\scriptscriptstyle ON}}/{I}_{ \mathrm{\scriptscriptstyle OFF}}$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 10^{{4}}$ </tex-math></inline-formula> with an operating voltage of −5 V. Apart from high electrical stability upon bias stress and repeated measurement of transfer curves, these devices showed excellent stability in electrical performance upon being subjected to sequential bending in various directions, i.e., vertical, horizontal, and diagonal to the channel length. Even after the application of 500 cycles of bending, no significant degradation in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{ \mathrm{\scriptscriptstyle ON}}$ </tex-math></inline-formula> was observed. This very high electromechanical stability in devices was achieved due to a super strong and highly tough hydrogen-bonded polyelectrolyte/polymer bilayer dielectric. In addition, external resistor-loaded inverters were also demonstrated with these devices to evaluate the circuit performance.