New materials to promote LED lighting technology revolution

LED with power saving features are becoming more and more popular in solid state lighting solutions, and researchers say the technology will make LED more widely used. Researchers in the United States say they are working on a "revolutionary solid-state lighting technology" through the use of new materials. Rensselaer Polytechnic Institute (RPI) research project lighting engineering research center of intelligent leader FredSchubert said: "the high output power of LED for the past ten years are using the same material, our new scheme is to change the existing LED activity (activeregion) of the key elements; we believe that this will change in solid-state lighting technical reform of whole world. He expected that the new technology in the current size of $10 billion in the global LED market, the application of 75% of the product.

Now, LED is a material of gallium nitride indium (quantumwELls), which is sandwiched between the thick Gan barrier layer (barrierlayers). In between the two kinds of materials, the corresponding fragment (relativefraction) can make the color of light into purple to amber; polarization mismatch between two kinds of materials (polarizationmismatch) will lead to electronic leakage, and reduce the effectiveness of LED in the application of high level of output.

Gallium nitride is a relatively simple material, but it will not form a polarization match with Gan gan. "Schuert said:" this mismatch is the physical cause of high output power LED efficiency dips (Efficiencydroop). "The high efficiency of the output power of the LED phenomenon, so that the output power of such products is higher, the energy consumption per lumen more. Schuert pointed out that this is a key disadvantage of solid-state lighting technology in the market.

Including members from Samsung Motors (SamsungElectro-Mechanics) engineer, Schuert's team claimed that they through the indium gallium nitride layer using polarization matching to replace Gan, so the efficiency drop of the condition can reduce to 25% in high power situation. Schuert said that the use of polarization matching materials to bring a lot of change, although not perfect, but they believe in the field of solid-state lighting for high power LED applications is very important.

Large scale polarization mismatch between materials means that electrons will start to run with the current, and then move back and forth with the current when they move to a position where they can be recombined. Schuert said that by matching these polarization fields, not only can improve the efficiency of LED, but also can reduce the forward voltage (forwardvoltage). The ideal LED efficiency should be around 300 lumens per watt, but even the most efficient experimental prototype, its efficiency is only up to 170 lumens per watt. Under the joint efforts of Samsung and RPI, Schubert is confident that within a few years can produce 200 lumens per watt LED products.