The contrast ratio improvement of perovskite nanocrystals LEDs devices based on carbon nanotubes

Light emitting diodes (LEDs) are showing explosive growth in the display filed. To obtain high quality color performance display devices, ultraviolet excitation of quantum dots has become an effective solution. However, its contrast ratio (CR) performance limits its further development. Herein, for attaining high CR and color purity display performance, we combined the CsPbBr3/Cs4PbBr6 perovskite nanocrystals (Pero NCs) and carbon nanotubes (CNTs) for LED package. Although the light output combined with CNTs is decreasing because of the CNTs light absorption property, the CR is improved due to the reduced reflectance. Therefore, the green LED with the appropriate CNT concentration could balance the light emission and CR performance. Result shows that with 0.2% CNTs, the green Pero NCs LED boosts the contrast by 18.02% under 50 lx ambient illuminance while the luminous flux drops by 25.0% under 50 mA. And the color purity could be guaranteed over 84% at this CNT concentration. This study provides a better understanding of perovskite NCs LED and guidance on the contrast ratio improvement.