UVC-LED is known as a deep ultraviolet LED. The application development and disinfection efficiency of UVC-LED modules are important problems encountered when UVC-LED products are rushed into commercialization. In this article, a specific disinfection experiment with a UVC-LED module was combined to analyze the disinfection efficiency. UVC-LEDs with wavelengths of 260 and 280 nm were used and supplemented with UVA-LEDs with wavelengths of 360 and 390 nm. The module was packaged to investigate the inactivation of Escherichia coli and Staphylococcus aureus. Two new findings were obtained through the analysis and comparison of the experiments. First, the short wavelength from UVA might have an enhanced destructive effect on microorganisms when the radiation intensity of UVA-LED was sufficient with coupling UVA and UVC. Second, 260 nm UVC-LED lamp beads might have a shorter response time to inactivate microorganisms than 280 nm UVC-LED lamp beads. Bactericidal experiments near the surface and different radiation distances showed that the inactivation rate reached 99.9% after 1 min of exposure when the UVC-LED module was set at 260 or 280 nm wavelength lamp beads for disinfection. The disinfection efficiency of 280 nm UVC-LED lamp beads was higher than that of 260 nm UVC-LED lamp beads because of the increased UV intensity. The radiation distance was within 7.5 cm range, the exposure time was 60 s, the inactivation rate was over 99.9%, and the disinfection effect was remarkable. For current UVC-LED applications, such as near-surface UVC-LED, disinfection and air purification products have a high value.@en

Using first-principles calculation, we have studied the adsorption effect of small gas molecules (H₂O, CO₂, CH₄, SO₂, H₂S, and NH₃) on GeP₃ monolayer. To determine the most stable adsorption site, five adsorption sites (center, Ge, P, bridge GeP, and bridge PP) were considered in the paper. Through calculations of adsorption energy, adsorption distance, and charge transfer, we preliminarily determined that H₂O, CO₂, and CH₄ were physically adsorbed on GeP₃ via weak van der Waals force. However, SO₂, H₂S, and NH₃ were chemically adsorbed on GeP₃ with new covalent bonds formed, as concluded by calculations of electron localization function and charge density difference. Gas molecule adsorption can cause significant changes in the band gap of single-layer GeP₃, indicating that pristine GeP₃ monolayer is sensitive to these gases. In addition, the adsorption energy of the H₂O, CO₂, and CH₄ adsorbed on GeP₃ can be tuned effectively by employing an external electric field. Our theoretical studies reveal that GeP₃ monolayer is a promising gas-sensitive material used in nanometer devices.                                                                                                    

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