Recently, UVC LEDs, which emit deep ultraviolet light, have found extensive applications across various fields. This study demonstrates the design and implementation of thin films of three-dimensional photonic crystals (3D PhCs) as reflectors to enhance the light output power (LOP) of UVC LEDs. The 3D PhC reflectors were prepared using the self-assembly of silica nanospheres on a UVC LED lead frame substrate via the evaporation-induced method (side) and the gravitational sedimentation method (bottom), respectively. These PhCs with the (111) crystallographic plane were deposited on the side wall and bottom of the UVC LED lead frame, acting as functional materials to reflect UVC light. The LOP of UVC LEDs with 3D PhC reflectors at a driving current of 100 mA reached 19.6 mW. This represented a 30% enhancement compared to commercial UVC LEDs with Au-plated reflectors, due to the UVC light reflection by the photonic band gaps of 3D PhCs in the (111) crystallographic plane. Furthermore, after aging tests at 60 °C and 60% relative humidity for 1000 h, the relative LOP of UVC LEDs with 3D PhC reflectors decreased by 7%, which is better than that of commercial UVC LEDs. Thus, this study offers potential methods for enhancing the light output efficiency of commercial UVC light-emitting devices.
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http://dx.doi.org/10.3390/nano14110983 | DOI Listing |
J Hazard Mater
November 2024
School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong; Department of Architecture and Civil Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong. Electronic address:
Ultraviolet germicidal irradiation (UVGI) technology can inhibit the environmental transmission of airborne pathogens, but the dose-response behavior of airborne human coronavirus and wavelength-specific inactivation mechanisms are not well understood. This study investigated three competitive UVC sources for their inactivation efficacy and mechanisms against human coronavirus OC43 (HCoV-OC43). Results showed the following order of inactivation efficacy: 222-nm KrCl excimer lamp > 263-nm UV-LEDs > 254-nm low-pressure mercury lamp.
View Article and Find Full Text PDFAppl Environ Microbiol
November 2024
Department of Food and Animal Sciences, Tennessee State University, Nashville, Tennessee, USA.
The airborne transmission of infectious diseases and bioaerosol-induced cross-contamination pose significant challenges in the food, dairy, and pharma industries. This study evaluated the effectiveness of 279 nm UV-C LED irradiation for decontaminating bioaerosols, specifically containing microorganisms such as (C3040- Kanamycin resistant), Enteritidis (ATCC 4931), and (ATCC 4973), on food contact surfaces. Borosilicate glass, silicon rubber, and stainless steel (316L) surfaces were selected for experimentation for their usage in the food industry.
View Article and Find Full Text PDFPLoS One
October 2024
Medical Affairs, Nanosonics Ltd., Sydney, Australia.
Medical devices that contact non-intact skin or mucous membranes are considered semi-critical devices and must undergo high-level disinfection (HLD) before use. Studies have identified several potential limitations of UV-C for HLD of semi-critical medical devices, including a lack of data demonstrating that UV-C irradiance can be uniformly applied to complex surfaces that contain grooves, notches and imperfections. This study focused on ultrasound probes as commonly used medical devices to show the distribution of irradiance on these surfaces.
View Article and Find Full Text PDFMicroorganisms
October 2024
Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, 89075 Ulm, Germany.
The contamination of surfaces by antibiotic-resistant pathogens presents an escalating challenge, especially on touchscreens in public settings such as hospitals, airports, and means of transport. Traditional chemical cleaning agents are often ineffective and leave behind harmful residues. Thus, the application of optical radiation is gaining relevance as a rapid, effective, and environmentally friendly disinfection method.
View Article and Find Full Text PDFNanomaterials (Basel)
October 2024
Centre of Excellence for Photoconversion, Vinča Institute of Nuclear Sciences-National Institute of the Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia.
Tunable blue/red dual-emitting Eu-doped, Bi-sensitized SrF phosphors were synthesized utilizing a solvothermal-microwave method. All phosphors have cubic structure (- (225) space group) and well-distinct sphere-like particles with a size of ~20 nm, as examined by X-ray diffraction and transmission electron microscopy. The diffuse reflectance spectra reveal a redshift of the absorption band in the UV region as the Bi concentration in SrF: Eu phosphor increases.
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