The problem with the latter is that it tends to generate a very cool light with a blue tinge, while the former is less energy efficient because of their reliance on green LEDs.

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When combined with the rest of the blue this forms a cool, white light.

ECONOMIST: Lighting: A brilliant new approach | The

After the researchers had allowed their wafer to cool, they bathed it in ultraviolet light and saw that some of the squares glowed bright blue.

ECONOMIST: Combinatorial chemistry