High color rendering index and stable white light emitting diodes fabricated from lead bromide perovskites

The tunable wavelength and high photoluminescence quantum yield of metal halide perovskite quantum dots (QDs) make them an extraordinary material for white light-emitting diodes (WLEDs). However, when perovskites with different halides are mixed, anion exchange occurs between them, limiting the development of WLEDs based on the perovskite. Meanwhile, the red emitting perovskite containing iodine is not stable, which is also a problem to overcome. In this paper, only bromide perovskites were adopted to fabricate the WLED. Hence, the anion exchange reaction can be avoided during their mixing process. CsPbBr3 nanoplatelets, CsPbBr3 QDs, and Mn-doped PEA(2)PbBr(4) nanosheets were used as the blue, green, and red components of the WLEDs, respectively. All these perovskites preserve high luminance and stability, especially the red emitting component. Thus, the WLED shows high efficiency and excellent stability. By adjusting the amounts of these perovskites, WLEDs with different color temperatures were achieved, and the color rendering index reached up to 94.