Gas Dielectric Transistor of CuPc Single Crystalline Nanowire for SO₂ Detection Down to Sub‐ppm Levels at Room Temperature

Abstract

Sulfur dioxide (SO 2 ) is one of the most dangerous air pollutants that impair environment and human health. SO 2 in air is released during the burning of fossil fuels and plays one major role in the formation of acid rain. The repeated exposure to low levels of SO 2 can cause permanent pulmonary impairment for humans. [ 1 ] The long and short-term exposure limits for SO 2 gas are 2 and 5 ppm, respectively, [ 1 , 2 ] and the U. S. Environmental Control Agency has set the acceptable limit for SO 2 in ambient air at a level of 0.5 ppm. [ 3 ] It is of great importance to measure low concentration of SO 2 in air accurately and fast for human health protection and air-quality monitoring.Semiconductor resistor sensors are, for more than 30 years, one of the most common used gas sensors to detect toxic and fl ammable gases such as NO 2 , H 2 S, CO, NH 3 , and H 2 because of their distinguished merits such as low cost, long lasting, high sensitivity, and good reliability, etc. [ 4 ] Organic fi eld-effect transistor (OFET) is another alternative semiconductor sensing technology with advantages over resistors, and has attracted much attention only recently. [ 5 ] The sensitivity can be dramatically enhanced by changing the source-drain current ( I SD ) of OFET when operating the sensors in the sub-threshold regime, as a result of the current modulation by the extra gate electrode. [ 6 ] Another advantage of OFET sensors is that the sensing response can be enhanced by integrating them in oscillator and adaptive amplifi er circuits. [ 7 ] These advantages combined with low cost and light weight of organic semiconductors ensure that OFET sensors have attracted much attention for the detection of a wide range of gases. [ 8 ] However, only few efforts have been made to develop the semiconductor SO 2 sensors and almost all of them are resistortype (a detailed performance list for the reported semiconductor SO 2 sensors is shown in Supporting Information Table S1). The semiconductor materials are mainly focused on metal oxide, such as SnO 2 , WO 3 and TiO 2 . Most reported semiconductor SO 2 sensors require an operating temperature of 200-600 ° C, demonstrate a sensitivity lower than 50%, face challenges in low concentration detection, or suffer from a slow response and recovery time of over 10 min.In this communication, an OFET based on gas dielectric and CuPc single crystalline nanowire as a novel SO 2 sensor with complete recovery and room-temperature detection is reported.To the best of our knowledge, this is the fi rst demonstration of SO 2 gas sensing based on OFETs. The sensitivity is characterized by the enhanced fi eld-effect mobility and is as high as 764% in 20 ppm SO 2 . The detect limitation is down to sub-ppm levels (0.5 ppm) with high sensitivity (119%) and high resolution (100 ppb). The exposed conductive channel is shown to be responsible for the sensitivity to SO 2 . Figure 1 a shows a schematic image of the gas dielectric fi eldeffect transistor (FET) sensor based on CuPc nanowire and the adsorption of SO 2 ...

Controllable preparation of copper phthalocyanine single crystal nano column and its chlorine gas sensing properties

“…Shaymurat et al reported OFET based on CuPc single crystalline nanowire as a novel SO 2 sensor which the detect limitation is down to sub-ppm levels. 4 Miyata et al prepared MPc thin films Cl 2 gas sensor using vacuum deposition, and Cl 2 with a minimum concentration of 0.18 ppm could be detected in the operating temperature range from 25 to 200 • C. 13 In this paper, we demonstrated template-free preparation and device integration of singlecrystalline CuPc nano column for room temperature Cl 2 detecting at ppb level. The rectangular section CuPc nano column can be controlled and grown on quartz, glass, sapphire, silicon and SiO 2 /Si substrates, proving that the aligned growth of nano columns is not substrate-dependent.…”

“…3,4 Geohegan group has prepared high-quality single-crystalline nanowires with good control over the wire structure and morphology, and exploited organic field-effect transistors (OFETs) based on individual α-phase nanowires, which exhibits excellent performance. 5 Jie et al developed simultaneous patterned growth and device integration of cross-aligned single-crystalline organic nanowire arrays for optical image sensors.…”

“…Sensor technology has an important effect on many aspects of our society, and has widely aroused people's attentions. 4,12 Chlorine (Cl 2 ) is the staple product of chlor-alkali industry and commonly used household cleaner and disinfectant, which is considered to be one of the most dangerous air pollutants that impair environment and human health. So it is very necessary to monitor and the research focus is aimed at developing high-performance gas sensors with low operating temperature at low fabrication costs.…”

Assembly of π‐Conjugated Nanosystems for Electronic Sensing Devices

“…[78][79][80][81][82][83][84][85][86] Owing to the intrinsic merits of CPs and OSCs, such as their tremendous variety with regard to molecular engineering, light weight, low cost, mechanical flexibility, and room-temperature operation capability, etc., most of the disadvantages of inorganic semiconductors-based sensor could be avoided, rendering the CPs-or OSCs-based counterparts promising alternatives. [1,15,87] Nevertheless, most of the investigations focus on gas sensors, wherein thin films of CPs or OSCs are used as active layer. [79,80] Most of these publications use thick active films with a response/recovery time of several minutes to dozens of minutes, preventing them from in situ sensing applications.…”

High mobility organic field-effect transistor based on water-soluble deoxyribonucleic acid via spray coating

“…26 Despite of the OSC/electrodes interface, the dielectric/ OSC interface is also crucial to the device performance as the trap sites at dielectric/OSC interface will significantly influence the charge transport, leading to the reduction of channel current and field-effect mobility. 27,28 The trap density (N SS ) presents the density of trap sites and is proportional to subthreshold slope (SS) as shown in Eq. (1) 29…”