Effect of Vertical Annealing on the Nitrogen Dioxide Response of Organic Thin Film Transistors.

Sihui Hou,Junsheng Yu,Xinming Zhuang,Zuchong Yang

doi:10.3390/nano8040203

Sihui Hou, Junsheng Yu + Show 2 more

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https://doi.org/10.3390/nano8040203

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Abstract

Nitrogen dioxide (NO2) sensors based on organic thin-film transistors (OTFTs) were fabricated by conventional annealing (horizontal) and vertical annealing processes of organic semiconductor (OSC) films. The NO2 responsivity of OTFTs to 15 ppm of NO2 is 1408% under conditions of vertical annealing and only 72% when conventional annealing is applied. Moreover, gas sensors obtained by vertical annealing achieve a high sensing performance of 589% already at 1 ppm of NO2, while showing a preferential response to NO2 compared with SO2, NH3, CO, and H2S. To analyze the mechanism of performance improvement of OTFT gas sensors, the morphologies of 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) films were characterized by atomic force microscopy (AFM) in tapping mode. The results show that, in well-aligned TIPS-pentacene films, a large number of effective grain boundaries inside the conducting channel contribute to the enhancement of NO2 gas sensing performance.

Highlights

In the process of human production and life, a large number of toxic and harmful gases, such as nitrogen dioxide (NO2), sulfur dioxide (SO2), and ammonia (NH3), are unavoidably emitted into the atmosphere
Well-aligned organic semiconductor (OSC) films can be obtained, in which the backbone of molecules interconnects in a certain orientation by weak non-covalent bonding interactions [14]. This method of morphology modification effectively controls the performance of organic thin-film transistors (OTFTs), and has great potential to improve the sensitivity of gas sensors
A simple vertical annealing process was proposed for the fabrication of high-performance OTFT based NO2 sensors

Summary

Introduction

In the process of human production and life, a large number of toxic and harmful gases, such as nitrogen dioxide (NO2), sulfur dioxide (SO2), and ammonia (NH3), are unavoidably emitted into the atmosphere. Film morphology is an important factor affecting those parameters of OTFTs. By specific process engineering, well-aligned organic semiconductor (OSC) films can be obtained, in which the backbone of molecules interconnects in a certain orientation by weak non-covalent bonding interactions [14]. Well-aligned organic semiconductor (OSC) films can be obtained, in which the backbone of molecules interconnects in a certain orientation by weak non-covalent bonding interactions [14] This method of morphology modification effectively controls the performance of OTFTs, and has great potential to improve the sensitivity of gas sensors. It’s still a challenge to get well-aligned OSC films

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Results

Conclusion