In-situ fabrication of ZnO nanoparticles sensors based on gas-sensing electrode for ppb-level H_(2)S detection at room temperature

The zinc oxide(ZnO)nanoparticles(NPs)sensors were prepared in-situ on the gas-sensing electrodes by a one-step simple sol-gel method for the detection of hydrogen sulfide(H_(2)S)gas.The sphere-like ZnO NPs were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),x-ray diffraction(XRD),energy dispersive x-ray analysis(EDX),and their H_(2)S sensing performance were measured at room temperature.Testing results indicate that the ZnO NPs exhibit excellent response to H_(2)S gas at room temperature.The response value of the optimal sample to750 ppb H_(2)S is 73.3%,the detection limit reaches to 30 ppb,and the response value is 7.5%.Furthermore,the effects of the calcining time and thickness of the film on the gas-sensing performance were investigated.Both calcining time and film thickness show a negative correlation with the H_(2)S sensing performance.The corresponding reaction mechanism of H_(2)S detection was also discussed.

Red organic light-emitting diodes based photobiomodulation therapy enabling prominent hair growth

Hair loss can cause psychological distress.Here,red organic light-emitting diode(OLED)light source is first introduced as the photobiomodulation therapy(PBMT)for hair growth and demonstrated as a promising and non-invasive therapeutic modality for alopecia.OLED exhibits unique advantages of homogeneous irradiation,flexible in form factor,less heat generation.These features enable OLED to be an ideal candidate for wearable PBMT light sources.A systematic study of using red OLEDs to facilitate hair growth was conducted.The results show that OLEDs excellently promote hair regrowth.OLED irradiation can increase the length of the hair by a factor of 1.5 as compared to the control,the hair regrowth area is enlarged by over 3 times after 20 days of treatments.Moreover,the mechanism of OLED that stimulates hair follicle regeneration is investigated invivo by conducting a systematic controlled experiments on mice with or without OLED PBMT.Based on the comprehensive histological and immunofluorescence staining studies,two key factors are identified for red OLEDs to facilitate hair follicle regeneration:(i)increased autophagy during the anagen phase of the hair growth cycle;(ii)increased blood oxygen content promoted by the accelerated microvascular blood flow.

Synthesis and optical properties of Cu_2SnZnS_4 films under different sulfur atmospheres

The electrodeposited precursor is a mixture of Cu, Sn, and Zn alloys, these elements form Cu6Sn5 and CuZn binary phases, and subsequently these phases trans- form into many binary and ternary intermediates, such as CuS, ZnS, Cu2SnS3, and Cu2ZnSnS4 （CZTS） at low annealing temperature in pure sulfur and H2S atmospheres. Finally, CZTS films can be dizing at 550 ℃ for 1 h in completely formed by sulfi- pure sulfur and H2S atmo- spheres. However, the initial temperature of synthesizing CZTS in H2S atmosphere is higher than that in pure sulfur atmosphere, but the highest temperature of synthesizing CZTS in H2S atmosphere is lower than that in pure sulfur atmosphere. The direct band gaps of the CZTS films syn- thesized at 550 ℃ for 1 h in pure sulfur and H2S atmo- spheres are about 1.54 and 1.52 eV, respectively.