Photochromism is a chemical process in which a compound undergoes a reversible change between two states having separate absorption spectra, i.e. different color [1]. In our previous work we have published some soluti...Photochromism is a chemical process in which a compound undergoes a reversible change between two states having separate absorption spectra, i.e. different color [1]. In our previous work we have published some solutions of problems of measuring photochromic textile sample by standard commercial spectrophotometric systems [2]. Main problem with measurement of kinetic behavior of photochromic pigments by standard spectrophotometer is relatively long time period between individual measurements (5 s) and impossibility of measuring whole color change during exposure without interruption of illumination of sample during measurement. It means, standard commercial spectrophotometers enable off-line measurement of kinetic behavior during exposure period and quasi on-line measurement during reversion period. Based on this problem, it is only possible to obtain precise data during reversion—decay process and growth process (exposure) is affected by high variability of data. Following this knowledge, we developed original experimenttal system with short time scanning of color change of photochromic samples during growth and decay period of color change. In this study it is presented new view on the relationship between intensity of UV-A radiation and color change half-life t1/2. Via this relation, it is demonstrated the possibility of the flexible textile-based sensors construction in the area of the radiation intensity identification.展开更多
A wearable UV sensor is designed to realize UV detection and a warning effect on people’s excessive UV exposure.It is noteworthy that the photoelectric system and supporting material of the most conventional sensor a...A wearable UV sensor is designed to realize UV detection and a warning effect on people’s excessive UV exposure.It is noteworthy that the photoelectric system and supporting material of the most conventional sensor are separated.The unstable connection between the two components and the complicated construction method makes the sensor susceptible to external motion interference and prone to failure.Herein,we developed a unique photo response mode of the UV sensor based on a novel photo responsive material.An azobenzene-containing polydimethylsiloxane(Azo-PDMS)film was prepared as the outer layer of the sensor.It integrated the functions of photo response source,support and protection,which realized the direct contact and rapid response to the UV light source.Carbon nanotube(CNT),wrapped in the middle of Azo-PDMS films as an inner layer,transformed the photomechanical response signal into the photoelectric signal.The photo response mode endows the sensor with excellent anti-motion interference capabilities and a true sense of UV-strain synchronous monitoring performance,which is of great significance to the practical application of wearable devices.In addition,based on the excellent properties of Azo-PDMS,the sensor can also protect the human body from UV damage,self-repair after fracture,and realize personalized customization through 3 D printing.It makes a breakthrough in the design and construction of wearable UV sensors and paves a new way to optimize sensor photo response modes.展开更多
Fabrication temperature is an important factor affecting the manufacturability of electronic devices,especially for the bottom-up self-assembled nano-device.In this study,we used a lateral-bridged zinc oxide(ZnO)nanow...Fabrication temperature is an important factor affecting the manufacturability of electronic devices,especially for the bottom-up self-assembled nano-device.In this study,we used a lateral-bridged zinc oxide(ZnO)nanowire array UV sensor as a model to investigate the influence of temperature on device performance over the entire manufacturing process,from sensor fabrication to packaging.We found that annealing of the SiO2 substrate would make ZnO seed layer on top of it more compact and uniform,and hence improve the lateral orientation and uniformity of ZnO nanowires grown from the seed layer.With the annealed substrate,the light-to-dark current ratio increased by two orders of magnitude.On the contrary,annealing the ZnO seed layer would deteriorate the light-to-dark current ratio of the sensor,because annealing caused most of the grains in the seed layer to become vertically aligned,which in turn affected the lateral growth of ZnO nanowire arrays.During the packaging process,the surface structure of ZnO nanowires would change if the chip welded at a temperature of 230℃for 2 min,resulting in a decrease of light-to-dark current ratio by three orders of magnitude.展开更多
SnO2-ln2O3 hierarchical microspheres were prepared by the hydrothermal and solvothermal method. The morphology, phase crystallinity of the obtained SnO2-In203 were measured by X-ray diffraetion（XRD）, scan electron m...SnO2-ln2O3 hierarchical microspheres were prepared by the hydrothermal and solvothermal method. The morphology, phase crystallinity of the obtained SnO2-In203 were measured by X-ray diffraetion（XRD）, scan electron microscopy（SEM）, respectively. A room temperature ozone sensor based on SnO2-In2O3 hierarchical microspheres was fabricated and investigated. The gas sensing properties of the sensor using SnO2-In2O3 strongly depended on the proportion of SnO2 and In2O3. The sensitivity and response/recovery speed were greatly enhanced by UV illumination. A gas sensing mechanism related to oxygen defect was suggested.展开更多
ZnO nanosheets with thickness of a few nanometers are prepared by vapor transport and condensation method, and their structure and optical properties are well characterized. Field effect transistor （FET） and ultravi...ZnO nanosheets with thickness of a few nanometers are prepared by vapor transport and condensation method, and their structure and optical properties are well characterized. Field effect transistor （FET） and ultraviolet （UV） sensors are fabricated based on the ZnO nanosheets. Due to the peculiar structure of nanosheet, the FET shows n-type enhanced mode behavior and high electrical performance, and its field-effect mobility and on/off cur- rent ratio can reach 256 cm2/（V.s） and ~10^8, respectively. Moreover, the response of UV sensors can also be remarkably improved to ~3 × 10^8. The results make the ZnO nanosheets be a good material for the applications in nanoelectronic and optoelectronic devices.展开更多
文摘Photochromism is a chemical process in which a compound undergoes a reversible change between two states having separate absorption spectra, i.e. different color [1]. In our previous work we have published some solutions of problems of measuring photochromic textile sample by standard commercial spectrophotometric systems [2]. Main problem with measurement of kinetic behavior of photochromic pigments by standard spectrophotometer is relatively long time period between individual measurements (5 s) and impossibility of measuring whole color change during exposure without interruption of illumination of sample during measurement. It means, standard commercial spectrophotometers enable off-line measurement of kinetic behavior during exposure period and quasi on-line measurement during reversion period. Based on this problem, it is only possible to obtain precise data during reversion—decay process and growth process (exposure) is affected by high variability of data. Following this knowledge, we developed original experimenttal system with short time scanning of color change of photochromic samples during growth and decay period of color change. In this study it is presented new view on the relationship between intensity of UV-A radiation and color change half-life t1/2. Via this relation, it is demonstrated the possibility of the flexible textile-based sensors construction in the area of the radiation intensity identification.
文摘A wearable UV sensor is designed to realize UV detection and a warning effect on people’s excessive UV exposure.It is noteworthy that the photoelectric system and supporting material of the most conventional sensor are separated.The unstable connection between the two components and the complicated construction method makes the sensor susceptible to external motion interference and prone to failure.Herein,we developed a unique photo response mode of the UV sensor based on a novel photo responsive material.An azobenzene-containing polydimethylsiloxane(Azo-PDMS)film was prepared as the outer layer of the sensor.It integrated the functions of photo response source,support and protection,which realized the direct contact and rapid response to the UV light source.Carbon nanotube(CNT),wrapped in the middle of Azo-PDMS films as an inner layer,transformed the photomechanical response signal into the photoelectric signal.The photo response mode endows the sensor with excellent anti-motion interference capabilities and a true sense of UV-strain synchronous monitoring performance,which is of great significance to the practical application of wearable devices.In addition,based on the excellent properties of Azo-PDMS,the sensor can also protect the human body from UV damage,self-repair after fracture,and realize personalized customization through 3 D printing.It makes a breakthrough in the design and construction of wearable UV sensors and paves a new way to optimize sensor photo response modes.
基金supported by the National Natural Science Foundation of China(Grant No.11204009)the Beijing Municipal Natural Science Foundation(Grant Nos.4142005 and 4182014)Beijing Education Commission Science and Technology Program(Grant No.KM201810005025)。
文摘Fabrication temperature is an important factor affecting the manufacturability of electronic devices,especially for the bottom-up self-assembled nano-device.In this study,we used a lateral-bridged zinc oxide(ZnO)nanowire array UV sensor as a model to investigate the influence of temperature on device performance over the entire manufacturing process,from sensor fabrication to packaging.We found that annealing of the SiO2 substrate would make ZnO seed layer on top of it more compact and uniform,and hence improve the lateral orientation and uniformity of ZnO nanowires grown from the seed layer.With the annealed substrate,the light-to-dark current ratio increased by two orders of magnitude.On the contrary,annealing the ZnO seed layer would deteriorate the light-to-dark current ratio of the sensor,because annealing caused most of the grains in the seed layer to become vertically aligned,which in turn affected the lateral growth of ZnO nanowire arrays.During the packaging process,the surface structure of ZnO nanowires would change if the chip welded at a temperature of 230℃for 2 min,resulting in a decrease of light-to-dark current ratio by three orders of magnitude.
基金Supported by the National Natural Science Foundation of China(Nos.60906036,61074172,61134010)the Program for Changjiang Scholars and Innovative Research Team in Universities of China(No.IRT1017)
文摘SnO2-ln2O3 hierarchical microspheres were prepared by the hydrothermal and solvothermal method. The morphology, phase crystallinity of the obtained SnO2-In203 were measured by X-ray diffraetion（XRD）, scan electron microscopy（SEM）, respectively. A room temperature ozone sensor based on SnO2-In2O3 hierarchical microspheres was fabricated and investigated. The gas sensing properties of the sensor using SnO2-In2O3 strongly depended on the proportion of SnO2 and In2O3. The sensitivity and response/recovery speed were greatly enhanced by UV illumination. A gas sensing mechanism related to oxygen defect was suggested.
文摘ZnO nanosheets with thickness of a few nanometers are prepared by vapor transport and condensation method, and their structure and optical properties are well characterized. Field effect transistor （FET） and ultraviolet （UV） sensors are fabricated based on the ZnO nanosheets. Due to the peculiar structure of nanosheet, the FET shows n-type enhanced mode behavior and high electrical performance, and its field-effect mobility and on/off cur- rent ratio can reach 256 cm2/（V.s） and ~10^8, respectively. Moreover, the response of UV sensors can also be remarkably improved to ~3 × 10^8. The results make the ZnO nanosheets be a good material for the applications in nanoelectronic and optoelectronic devices.
