Computer graphics are taken for granted today. But it has been a long and painful struggle, with hardware rarely keeping up with the demand for better images. In English, there are a relatively small number of characters which comprise text. The same is not true of images: graphics are computationally intensive. They always seem to take as much speed and memory as there are available. But the demand was high enough that early computer graphics could be fairly crude and still be in demand.
By combining carbon dots that emit blue light and zinc copper indium sulphide quantum dots that emit in the green and red regions of the electromagnetic spectrum, researchers in China and the US have succeeded in making white light-emitting diodes with a high colour-rendering index of 93. The devices might find use in solid-state lighting and displays.
