A light-emitting diode, commonly referred to as an LED, is a simple semiconductor device that uses little energy to release light when a current passes through it. The wavelength of light emitted depends on what material is used to make up the...

LEDs (light-emitting diodes) can often be found in electronic toys, science kits, calculators, and many other household devices. LEDs are first and foremost diodes, special kinds of crystals or transistors that allow electrical current to pass through...

A light-emitting diode (LED) /ɛl.i.ˈdiː/[1] is a semiconductor diode that emits incoherent narrow-spectrum light when electrically biased in the forward direction of the p-n junction, as in the common LED circuit. This effect is a form of...

In this age of high energy prices, there are increased efforts to use light sources that are more energy efficient than incandescent light bulbs. Here we will consider one such light source. Perhaps in future columns, we will look at other types of light...

ARNO KRAFT, Heriot-Watt University, Edinburgh Combinatorial methods are starting to make significant contributions towards materials design and development (R Dagani, Chem. Eng. News, 8 March 1999, 51; B Jandeleit, J Schaefer, et al, Angew. Chem. Int. Ed., 1999, 38, 2476). It is,...

The famous necklace lights on the Brooklyn Bridge will go "green" next year as part of several environmental upgrades around the city, officials said Wednesday.Changing 160 lights on the landmark bridge, which turns 125 years old next year, is expected to cost $500,000. Other city...