Colorimetry and efficiency of white LEDs: Spectral width dependence

The Impact of Spectral Composition of White LEDs on Spinach (Spinacia oleracea) Growth and Development

Light-emitting diodes (LED) are a promising light source for the cultivation of edible vegetables in greenhouses. The spectral radiation of the light sources has an impact on plants physiological parameters, as well as on morphological features. In this study the growth of spinach plants has been carried out in experimental boxes under two white LED treatments having different correlate color t...

Nanophosphors for White Light Leds

Precise slit-width control of niobium apertures for superconducting LEDs.

We introduce a novel three-step procedure for precise niobium (Nb)-etching on the nanometer-scale, including the design of high contrast resist patterning and sacrifice layer formation under high radio frequency (RF) power. We present the results of precise slit fabrication using this technique and discuss its application for the production of superconducting devices, such as superconductor-sem...

Thermophotonics for ultra-high efficiency visible LEDs

The wall-plug efficiency of modern light-emitting diodes (LEDs) has far surpassed all other forms of lighting and is expected to improve further as the lifetime cost of a luminaire is today dominated by the cost of energy. The drive towards higher efficiency inevitably opens the question about the limits of future enhancement. Here, we investigate thermoelectric pumping as a means for improving...

Long-term performance of white LEDs and systems

In this manuscript we describe two experiments. The first one is life testing of three commercial high-power phosphor-converted (pc) white LEDs under three different operating temperatures. The second is life testing of two commercial lighting systems that use highpower pc-white LEDs. Life testing was conducted per ASSIST recommends guidelines. Results showed that LED life is very much affected...