A Simple Device‐To‐Device Transform for White Light‐Emitting Diode with Monochromatic Carbon Dots

Abstract Currently, the fabrication of white light emitting diodes (WLEDs) strongly depends on white fluorescent emission materials. The conventional method, which is a direct way from the designed fluorescent emission material to the device, is regarded as a fundamental principle in this field. Here, a brand‐new approach is shown for the design of WLEDs with a simple device‐to‐device transform based on monochromatic carbon dots (CDs). In this work, the WLEDs based on the blue fluorescent CDs achieve the in situ generation of bright white light emission in the device, originating from the oxidation of functional groups involving S element in CDs caused by strong electrical treatment. These CDs‐based WLEDs possess the luminance of 533 cd m⁻², Commission Internationale d'Eclairage coordinates located at (0.38, 0.38), a correlated color temperature of 4072 K, and a color render index up to 95. This work opens a brand‐new gate for achieving high‐purity and bright WLEDs through the strategy of transforming from device to device rather than material to device.