Along with the revolution of the Internet of Things (IoT), smart, flexible, easily fabricated, and highly sensitive gas sensors are essential for many portable electronics. In this study, a wearable NO2 sensor based on a nanomesh structure woven with Ti3C2Tx microflakes and Bi2S3 nanobelts operated at room temperature was successfully designed and prepared. The effects of the mass ratio between two materials on the performance were evaluated. Bi2S3 nanobelts embedded inside accordion-like Ti3C2Tx provide large specific surface areas and abundant active sites for the adsorption of NO2 molecules. Attributed to the high conductivity of Ti3C2Tx, the carriers generated in the sensitive layers are easily transmitted during sensing, thus significantly reducing the response and recovery times. The sensor based on the nanomesh containing 30 wt % Ti3C2Tx exhibits excellent sensing performance, fast response/recovery rates, and high stability even in arbitrary deformed shape conditions. Upon exposure to 1 ppm NO2, the response of the sensor is 12.67, and the response/recovery times are 5/28 s, respectively. A stable sensing performance can be maintained after 1500 cycles of deformation. This work demonstrates a simple but reliable manufacturing strategy of wearable gas sensors for the next generation of IoT monitoring network-linking human activities.
Chong Li,Hao Kan,Jingting Luo,Chen Fu,Jian Zhou,Xueli Liu,Wen Wang,Qiuping Wei,Yongqing Fu
Low dimensional Bi2S3 materials are excellent for use in photodetectors with excellent stability and fast response time. In this work, we developed a visible light sensor with good performance based on surface acoustic wave (SAW) devices using Bi2S3 nanobelts as the sensing materials. The SAW delay-line sensor was fabricated on ST-cut quartz with a designed wavelength of 15.8 microns using conventional photolithography techniques. The measured center frequency was 200.02 MHz. The Bi2S3 nanobelts prepared by a facile hydrothermal process were deposited onto SAW sensors by spin-coating. Under irradiation of 625 nm visible light with a power intensity of 170 μW cm−2, the sensor showed a fast and large response with a frequency upshift of 7 kHz within 1 s. The upshift of the frequency of the SAW device is mainly attributed to the mass loading effect caused by the desorption of oxygen from the Bi2S3 nanobelts under visible light radiation.
Along with continuous growing widespread adulterations of botanical drugs, the necessity for drug quality monitoring has become more popular than ever. Considering that antioxidants are widely found in natural plant pharmaceuticals, gallic acid (GA) is often regarded as the reference standard to make sure whether these are up to grade as guided by Chinese Pharmacopeia. Herein, a novel Bi 2 MoO 6 /Bi 2 S 3 photoelectrochemical sensor has been successfully involved toward selective GA analysis to supervise drug quality, in which γ-Bi 2 MoO 6 nanobelts were treated as template nanocrystal and scaffold. Such Bi 2 S 3 accommodated in Bi 2 MoO 6 nanobelts render platform with excellent light-harvesting capability, selectivity and reproducibility. Concerned mechanism was in-depth pursued through theoretical computation and morphology speculation, inferring that two aspects mainly contribute to the findings: (1) engineering particular structure brings about surface dangling bonds , which raises the likelihood of electrostatic interaction with opposite charges; (2) appending Bi 2 S 3 to the Bi 2 MoO 6 nanobelts acted as a new avenue to mediate photoelectrochemical behavior, nearly devoid of interference effect. Our work opens up broad possibilities for finely distinguishing different antioxidants. As the extension of this simple and valid strategy, photoelectrochemistry will become a potent backing for quality guaranty in drug field, which offers an entry into ensuring good consistency in batch production .
危险品化学品经营许可证（带存储）