Perovskite/Organic Hybrid White Light-Emitting Diodes with Excellent CIE Chromaticity Coordinate

Perovskite light-emitting diodes (PeLEDs) have great potential in solid-state lighting and display fields due to their advantages of narrow emission spectrum, excellent optoelectronic properties, simple preparation process, and low cost. However, the compatibility of solvents used in the full solution process substantially hindered the development of multilayer white PeLEDs. Although mixing perovskite and organic materials can avoid this problem, it remains challenging to manufacture white PeLEDs that are close to the Commission Internationale de L’Eclairage (CIE) coordinate of (0.33,0.33). In this paper, the perovskite/organic hybrid white light-emitting diodes composed of a bottom blue perovskite light-emitting unit prepared through a solution method and an organic light-emitting unit fabricated by thermal evaporation are reported. To enhance carrier transport and adjust the recombination region, we employed several strategies: improving the perovskite surface with phenylethylammonium bromide additive, optimizing the thickness of the organic red emission layer, inserting a lithium fluoride layer, and incorporating a blue supplementary emission layer. The best white PeLED shows a maximum luminance of 2281 cd/m2, a maximum external quantum efficiency of 2.64%, a CIE coordinate close to the equal-energy white point of (0.33,0.34), and a correlated color temperature of 5206 K. The results presented in this paper provide a feasible method for obtaining white PeLEDs with excellent CIE coordinates.