Important progress in the research of organic transistor sensors in Tongji University

The detection of hazardous chemicals is essential in environmental protection, food safety, medical and health, industrial production, and defense and military. The sensitivity to light, temperature and pressure is known in artificial intelligence, human-machine interface, intelligent robots, and labor. Frontier scientific research fields such as electronic skin and wearable devices are also extremely important. The FET-based sensor combines the functions of sensing and signal amplification, and has the advantages of simple portability, high sensitivity and high selectivity, and some organic semiconductor materials have the potential of biocompatibility and degradation. Therefore, organic transistor sensors are in the above research. Great use with the field of application.

Professor Huang Jia from the School of Materials Science and Engineering, Tongji University, under the support of the National “Thousand Talents Program”, the key research and development projects of the Shanghai Municipal Science and Technology Commission and the National Natural Science Foundation, the organic transistor sensor and the green and biosafety flexible electronics. A series of important advances have been made in the device. Some of the research results were published in the Journal of the American Chemical Society Advanced Materials, Advanced Functional Materials, ACS Nano, and Advanced Science. (Advance Science) is a high-level internationally renowned journal.

In recent years, Dr. Wu Xiaoyu, an assistant professor of the research group, has published more than 10 SCI papers under the support of the National Natural Science Foundation of China and the Shanghai Science and Technology Commission Talent Project “Sail Fan Program”. Some of the results were published in the first/common correspondence authors in “Advanced Functions”. Advanced Functional Materials (2) Advanced Science (Advance Science) (2) and Journal of Materials Chemistry A.

In the research and development of organic transistor chemical sensors, sensing of gas and liquid has been realized, but rapid and direct detection of solid powder samples has not been realized. The detection of harmful chemicals in solid powder, such as the rapid and direct detection of melamine in milk powder, has great scientific significance and application value. Huang Jia's research group designed and prepared a new type of sensor based on the shoulder-and-shoulder organic diode structure (Fig. 1), which realized the sensitive detection of trace solid chemicals in powder samples, and can effectively detect the far content contained in the solid powder after contacting the sample. Very low concentrations of melamine below our food safety standards. The research results were recently published in the International Top Journal of Chemistry, Journal of the American Chemical Society (2017) 139, 12366. Impact Factor 13.9.

Figure 1. Schematic of the components and devices of a new sensor based on a shoulder-to-shoulder diode structure.

The research team also designed and fabricated a micro-nano-hole organic field-effect transistor gas sensor, which uses the mechanism of rapid interaction between gas molecules and the field-effect transistor conductive channel, which significantly improves the sensitivity of the sensor. Sensitivity to ammonia is more than 340% m, can show a significant response to ammonia gas with a concentration lower than one-hundredth of a percent. The detection limit is the highest record of similar devices when the paper was published. The results were published in the famous journal “Advanced Functional Materials”. 2017) 27, 1700018. Impact factor 12.1]. In addition, the research team also cooperated with the Environmental College Li Zhuo teacher to achieve effective monitoring of the very low concentration of disinfection by-products in drinking water. The research results were recently published in the Journal of Materials Chemistry A. 5, 4842. Impact factor 8.9].

In the research field of photosensitive sensors, Huang Jia's research group successfully used organic phototransistors (Fig. 2) to simultaneously exhibit optical response of more than 10000 A/W by utilizing the complementary advantages of inorganic perovskite quantum dots and organic semiconductor composites. More than 1014Jone's light sensitivity limit and excellent stability, it achieves multi-parameter collaborative high performance that is difficult to obtain in previous research. The research results have just been accepted by Advanced Materials. (2017) Accepted, the top journal in materials field. DOI: 10.1002/adma.201704062. Impact factor 19.8] Receive.

Figure 2. Phototransistor based on inorganic perovskite quantum dots and organic semiconductor composites

The research group prepared a photosensor with adjustable response wavelength by low-cost solution method by organic layer intercalation control of semiconductor molecular structure. The related results were published in ACS Applied Materials & Interfaces. (2016) 8, 25660. Impact factor 7.5]. He was also invited to write a review of the field of photosensitive sensors. The paper was published in the famous journal "Advanced Science. (2017) Accepted, DOI: 10.1002/advs.201700256. Impact factor 9.0].

Dielectric/semiconductor layer interface charge effects are widely present in organic field effect transistors and often adversely affect device performance. Professor Huang Jia's research team used this interface effect, which is often considered to be a negative effect, to improve the sensitivity of the device, and prepared an artificial electronic skin with excellent temperature sensing performance. The research results are reported in Advanced Functional Materials. [Advanced Functional Materials. (2015) 25, 2138. Impact factor 12.1]. The group then prepared a photosensor based on the interface effect, and the results were published in Advanced Science [Advance Science. (2016) 1500435. Impact factor 9.0]. Professor Huang Jia previously worked with the University of Maryland to combine biomaterials with organic semiconductors to produce degradable flexible electronic devices. The results were published in ACS Nano. [ACS Nano. (2013) 7, 2106. Impact Factor 13.9]. Recently, Huang Jia's group further prepared a device by inkjet printing using a biosafety, green degradable composite solution of polylactic acid and soluble organic semiconductor. The larger interface area makes the printed flexible device more photosensitive. Performance and related results are published in Advanced Functional Materials. (2017) 27, 1604163. Impact factor 12.1. Polylactic acid gives the device its overall flexibility and bio-safety, and amplifies the layer interface charge effect of the device, which makes the sensing performance of the device significantly enhanced. It can be applied to temperature sensing of artificial skin, visual perception of artificial intelligence, etc. (Figure 3 ). The research team also conducted an in-depth systematic study on the mechanism of this interface charge effect, and proposed the direction and strategy of designing this type of sensor. The corresponding results have just been "Advance Science. (2017) Accepted, DOI: 10.1002 /advs.201700442. Impact factor 9.0] Receive. Dr. Wu Xiaoyu, an assistant professor of the research group, is the first author or co-author of this part of the research work on temperature sensitive photosensitive sensors.

Figure 3. Flexible temperature-sensitive photosensitive organic transistor sensor based on dielectric layer/semiconductor layer interface effect

This series of work provides new strategies and new ideas for the development and optimization of organic transistor sensors, and broadens the application range of such devices.