South Korea has developed a highly efficient organic light emitting diode (OLED) light source that can replace widely used incandescent bulbs. The new light source can attain 70 lumens per watt, which is more than four times the efficiency of regular light bulbs that account for roughly 50 percent of the world's lighting market, the Electronics and Telecommunications Research Institute (ETRI) said.

OLED can emit light from flat surfaces, has high energy efficiency that can help reduce greenhouse gas emissions, and are more eco-friendly since they do not use mercury in the manufacturing process like incandescent and fluorescent bulbs. They have longer operating lives, although they may cost more to produce.