Polarized Emission in Chiral Quasi-2D Perovskite Light-Emitting Diode

Abstract

Chiral 2D perovskites synthesized using (R-+)-α-Methylbenzylamine (R-MBA) and (S–)-α-Methylbenzylamine (S-MBA) as barrier molecules exhibit chirality at low n values, as confirmed by circular dichroism (CD) analysis. The Anisotropy factor decreases significantly with increasing the n value, reaching 0.0032 for pure 2D perovskite. These synthesized quasi-2D chiral perovskites have been successfully integrated into light-emitting diodes (LEDs), demonstrating polarized emission for the first time. Remarkably, n = 3, R enantiomer achieves a total external quantum efficiency (EQE) of 12.1%, with polarized EQE of 4%. In the case of n = 2, the total EQE for both enantiomers is 4.3%, with polarized EQE of 3.4%, higher than the non-polarized EQE of 0.9%. Degree of Polarization (DOP) is employed to characterize the fraction of an electromagnetic wave that exhibits polarization. The DOP analysis reveals a significant increase for low dimensional perovskite. Particularly for n = 2, R enantiomer exhibits a DOP of 53% compared to 2.5% for the non-chiral molecule BzA. These findings demonstrate efficient polarized emission in 2D chiral perovskite LEDs, indicating promising avenues for advanced optical device applications.