Mixed-Ligand Chiral Quasi-2D Perovskites for Standard and Deep Blue CP-LEDs

This study presents the development of mixed-ligand quasi-2D perovskites ((2-PEA) x ( R/S -2-BA) 2 MA 1 Cs 1 Pb 3 Br 10+ x , x = 0.8, 1.6, 2.4) for circularly polarized light-emitting diodes (CP-LEDs). By utilizing the strong confinement effect of 2-phenylethylammonium (2-PEA) and the chirality of R / S -2-butylammonium ( R/S -2-BA), room-temperature circularly polarized luminescence (CPL) across the green to deep blue spectrum is achieved. The green CPL attributes to the transfer of spin-polarized excitons while the blue CPL originates from direct excitation of luminescent phases with intrinsic chirality. Finally, green and blue CP-LEDs under ambient are realized. Notably, standard and deep blue CP-EL is achieved based on 0.8PEA/( R/S -2-BA)- and 1.2PEA/( R/S -2-BA)-films with impressive electroluminescent asymmetry factors (0.122 and 0.175), highlighting the potential of chiral perovskites in CP-LEDs and opening avenues for the development of room-temperature full-color CP-EL display.