The thermal stability performances of the color rendering index of white light emitting diodes with the red quantum dots encapsulation

•The CdSe/ZnS core–shell QDs have high crystallinity and scattered evenly.•The CRI of the LED encapsulated with the red QDs and yellow phosphors was as high as 90.9.•The CRI of WLEDs with yellow phosphors and red QDs was more stable than that of the device with yellow and red phosphors.

Red phosphors are the traditional material used to improve the color rendering index (CRI) of white light emitting diode (WLEDs). In this paper, red quantum dots (QDs) were fabricated and coated on the blue LED chip to replace the red phosphors. By comparing the thermal performances of the CRI for the two WLEDs, we found that WLEDs with the encapsulation of yellow phosphors and red QDs exhibited higher CRI and lower sensitivity to temperature than those with the encapsulation of yellow and red phosphors. The CRI of WLEDs with yellow phosphors and red QDs was 90.9, and its range ability was only 0.3 when the environment temperature changed from 25 °C to 100 °C, while the CRI of WLEDs with yellow and red phosphors was as low as 81.8, and the change of CRI was 2.2 during the same temperature variation.