Reduced Self‐Absorption of Quasi‐2D Perovskites and Their Application in Color Conversion Layers

Abstract Lead halide perovskites (LHPs) have recently demonstrated great potential for color conversion layers (CCLs) in backlight displays due to their ultrahigh color purity and high photoluminescence quantum yield. However, the severe self‐absorption effect of LHPs due to small Stokes shift restricts their optical conversion efficiency (OCE) as CCLs. Herein, quasi‐2D perovskites are exploited and the ultrafast energy transfer mechanism is introduced. Using this approach, CCLs Stokes shift is increased and its self‐absorption coefficient is reduced by nearly threefold (from 6.2 × 10⁴ to 2.1 × 10⁴ cm⁻¹). Therefore, color conversion light‐emitting diodes based on quasi‐2D perovskites are demonstrated with an improved OCE of 30% and ideal working stability of 1% loss under blue light irradiation of 35 mW cm⁻² indicating their great potential for application in backlight display.