LEDs tagged posts

A new type of LED is made with crystalline substances known as perovskites. CREDIT Sameer A. Khan/Fotobuddy

Princeton engineers have refined the manufacturing of light sources made with crystalline substances, perovskites, a moreefficient and potentially lower-cost alternative to materials used in LEDs found on store shelves. The researchers developed a technique in which nanoscale perovskite particles self-assemble to produce more efficient, stable and durable perovskite-based LEDs. The advance, reported January 16 in Nature Photonics, could speed the use of perovskite technologies in commercial applications such as lighting, lasers and television and computer screens.

LEDs emit light when voltage is applied across the LED...

Ohio State University researchers have developed a technique to create light emitting diodes on metal foil. Image by Brelon J. May, courtesy of The Ohio State University.

Material created with high heat yields record power output density. With energy conservation expected to play a growing role in managing global demand, materials and methods that make better use of existing sources of energy have become increasingly important. Researchers reported this week they have demonstrated a step forward in converting waste heat – from industrial smokestacks, power generating plants or even automobile tailpipes – into electricity.

The work, using a thermoelectric compound composed of niobium, titanium, iron and antimony, succeeded in raising the material’s power output density dramatically by using...

In a pump-probe experiment, the pump laser pulse first excites the 2D material, and later, at controllable time-delays, the probe laser pulse returns to the energy-pumped site to provide information about the evolution of the pump’s effect on the material. In the ORNL experiment, absorption of pumped energy first generated two excitons, X1 and X2. Dissociation of these excitons through hole trapping at the substrate freed their electrons. Then the arriving probe pulse generated new electron–hole pairs, which joined the remaining free electrons to form trions T1 and T2. Credit: Oak Ridge National Laboratory, U.S. Dept. of Energy

Quasiparticles – excitations that behave collectively like particles – can be difficult to detect...