In our continued effort to address the challenges of selective sp3 C-H fluorination on complex molecules, we report a sensitized aliphatic fluorination directed by terpenoidal enones using catalytic benzil and visible light (white LEDs). This sensitized approach is mild, simple to set up, and an economical alternative to our previous protocol based on direct excitation using UV light in a speci...

ZnO-based light emitting diodes (LEDs) have been considered as a potential candidate for the next generation of blue/ near-UV light sources, [ 1 ] due to a direct wide bandgap energy of 3.37 eV, a large exciton binding energy of 60 meV at room temperature, and several other manufacturing advantages of ZnO. [ 2 ] While the pursuit of stable and reproducible p-ZnO is still undergoing, [ 3,4 ] het...

In this work, we investigate the performance improvement of N-polar AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) by inversion hole injection layer from to Ga-polar. The influence different points on and energy band DUV LED is systematically studied, principle explained in detail through analysis band. Furthermore, according simulation results practical application, an appropria...

We have studied the design, epitaxy, and performance characteristics of deep ultraviolet (UV) AlGaN light emitting diodes (LEDs). By combining tunnel junction polarization-engineered electron blocking layer, a maximum external quantum efficiency wall-plug 0.35% 0.21%, respectively, were measured for devices operating at ∼245 nm, which are over one order magnitude higher than previously reported...

Ultraviolet (UV) reactors used for disinfecting water and wastewater must be validated and monitored over time. The validation process requires understanding the photochemical properties of the pathogens of concern and the challenge microorganisms used to represent them. Specifically for polychromatic UV systems, the organisms' dose responses to UV light and their sensitivity across the UV spec...

Ultraviolet light emitting diodes (UV-LEDs) have attracted great interest in recent years. They can be used to polymerize coatings, such as those used for prefinished wood flooring. In this project, two lamps were compared for their suitability to be used on a wood flooring finishing line: a UV-microwave and a UV-LED lamp. Low heat emission was found for the UV-LED lamp compared to the UV-micro...

The effects of composition and p-doping profile of the AlGaN:Mg electron blocking layer (EBL) in 310 nm ultraviolet B (UV-B) light emitting diodes (LEDs) have been investigated. The carrier injection and internal quantum efficiency of the LEDs were simulated and compared to electroluminescence measurements. The light output power depends strongly on the temporal biscyclopentadienylmagnesium (Cp...

In this paper, the enhancement of light extraction efficiency in III–nitride-based light-emitting diodes (LEDs) with an array of microstructures is demonstrated numerically and experimentally at the near-ultraviolet (n-UV) spectral region. Two different microstructures are adopted to study the mechanism, including the shallow etching of microstructures on the indium–tin-oxide (ITO) p-contact an...

Development of wide-bandgap III-nitride semiconductors has been a subject of intense focus since the 1990s, primarily driven by the quest for blue lasers and high-brightness light-emitting diodes (LEDs). In parallel, III-nitrides have been studied extensively for use in ultraviolet (UV) photodetectors because they offer intrinsic visibleor solar-blind detection, which would eliminate the need f...

We present the results of a detailed analysis of the noise behavior of two CCD spectrometers in common use, an AvaSpec-3648 CCD UV spectrometer and an Ocean Optics S2000 Vis spectrometer. Light sources used include a deuterium UV/Vis lamp and UV and visible LEDs. Common noise phenomena include source fluctuation noise, photoresponse nonuniformity, dark current noise, fixed pattern noise, and re...