ABSTRACT. In recent years, the use of light emitting diodes (LEDs) has become commonplace in fluorescence microscopy. LEDs are economical and easy to couple to commercial microscopes, and they provide powerful and stable light that can be triggered by transistor-transistor logic pulses in the range of tens of microseconds or shorter. LEDs are usually installed on the epifluorescence port of the...

The shortest-wavelength color of light that is visible to the human eye is violet. As shown in Fig. 1, light with wavelengths shorter than 400 nm is called ultraviolet (UV) light: that from 300 to 400 nm is called near-UV light, that from 200 to 300 nm is called deep-UV light, and that shorter than 200 nm is called vacuum-UV light. Since vacuum-UV is absorbed by air, deep-UV light is the shorte...

UV InGaN and GaN single-quantum well structure light-emitting diodes (LEDs) were grown on epitaxially laterally overgrown GaN (ELOG) and sapphire substrates. When the emission wavelength of UV InGaN LEDs was shorter than 380 nm, the external quantum efficiency (EQE) of the LED on ELOG was much higher than that on sapphire, but only for highcurrent operation. At low-current operation, both LEDs ...

The KMg4(PO4)3:Eu(2+) phosphor was prepared by the conventional high temperature solid-state reaction. The crystal structure, luminescence and reflectance spectra, thermal stability, quantum efficiency and the application for N-UV LED were studied respectively. The phase formation and crystal structure of KMg4(PO4)3:Eu(2+) were confirmed from the powder X-ray diffraction and the Rietveld refine...

Ultraviolet (UV) water treatment techniques currently employ blacklight (UV-BL) lamps, which are energy intensive, short living and contain toxic materials, damaging the environment. Light emitting diodes (UV-LEDs) can offer an environmentally friendly alternative to UV-BLs, however their environmental impacts for have not been quantified yet. This study aims at investigating sustainability of ...

This paper presents a UV (ultraviolet) lithography apparatus that utilizes an array composed of UV-LED (light emitting diode) collimation modules as a micro-patterning light source for PCB (printed circuit board) fabrication. To provide a uniform (non-uniformity > 90%) and collimated (FWHM < ±2°) exposure area, hexagonal light source modules are disposed in a hexagonal array. Each module is con...

In this paper, we overview several of the critical materials growth, design and performance issues for nitride-based UV (< 400 nm) LEDs. The critical issue of optical efficiency is presented through temperature-dependent l]ilotoiull~inesccncc studies of various IJV active regions. These studies demonstrate enhanced optical efficiencies for active regions with Incontaining alloys ( InGrN, AIInGa...

Cinnamate-functionalised organic green emissive molecules can be UV-cured to give physically stable polymer films for use in white light hybrid LEDs.

In this study, the degradation of diclofenac (DCF), a frequently detected non-steroidal pharmaceutical, was evaluated by using UV-B and UV-C (265, 285, 310 nm) light-emitting diodes (LEDs) alone in combination with hydrogen peroxide (UV/H2O2) free chlorine (UV/FC). The DCF followed pseudo first-order kinetic, their trend reflected pattern molar absorption coefficients oxidants. A positive syner...