Air-stable, transparent flexible ambipolar organic thin film transistors based on CuPc-F16CuPc bi-channel structure

Yi Li,Xiujing Lin,Ruiqing Liu,Yanwen Ma,Weixin Zhou,Xiao Han,Pan Li,Yinghui Li,Zhendong Huang,Xiaomiao Feng

doi:10.1063/1.5039995

Abstract

We report the fabrication of air-stable, transparent flexible ambipolar organic thin film transistors based on CuPc and F16CuPc bi-channel films deposited under 10−1 Pa, by using graphene gate electrode, fluoropolymer Cytop dielectric layer, and Au source/drain electrodes on polyethylene terephthalate substrates. The devices show outstanding air-stability and high optical transparency of above 75% with electron and hole mobilities up to 0.031 and 0.029 cm2/V·s, respectively. The excellent ambipolar performance, along with the outstanding air-stability and high optical transparency, make CuPc-F16CuPc bi-channel transistors as a promising candidate for organic integrated circuits.

Highlights

Transparent and flexible optoelectronic devices, such as light-emitting diodes, transistors, sensors and batteries, are critical elements for flexible, portable and wearable electronics.[1–5] With the functions of switching and amplification, transparent and flexible transistors are considered as the most important building blocks in wearable electronics
There are few researches on the fabricating transparent flexible ambipolar organic thin-film transistors (OTFTs), which is considered as the ideal model to realize low power transparent flexible complementary circuits.[14–16]
Q-band of phthalocyanine molecule is observed in the region between 550 and 750 nm for the spectra of CuPc/Cytop/graphene/Polyethylene terephthalate (PET) and F16CuPc/Cytop/graphene/PET samples, which is due to the π–π∗ excitation between bonding and antibonding molecular orbital.[31,32]

Summary

INTRODUCTION

Transparent and flexible optoelectronic devices, such as light-emitting diodes, transistors, sensors and batteries, are critical elements for flexible, portable and wearable electronics.[1–5] With the functions of switching and amplification, transparent and flexible transistors are considered as the most important building blocks in wearable electronics. Zhu and Hu et al introduced a novel bi-channel structure to realize air-stable CuPc/F16CuPc ambipolar field-effect transistors.[25]. Compared to the conventional bilayer heterojunction ambipolar field-effect transistors, the devices based on bi-channel structure could reduce the injection barriers and avoid the process of optimizing the thicknesses. As revealed by our experimental results and theoretical simulations, the CuPc and F16CuPc films deposited under [10-1] Pa have the optimized molecular packing, charge transfer and contact resistance in the corresponding unipolar OTFTs, implying the promising applications in bichannel ambipolar devices. We fabricated transparent flexible ambipolar OTFTs based on CuPc and F16CuPc bi-channel structure. Bi-channel CuPc and F16CuPc films deposited under [10-1] Pa were used as organic active layers, which showed the good ambipolar field-effect characteristics

EXPERIMENTAL

RESULTS AND DISCUSSION

CONCLUSIONS