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

• Published in: Advanced optical materials 2024-11, Vol.12 (31), p.n/a
• Main Authors: Shpatz Dayan, Adva, Schneider, Avi, Azulay, Doron, Paltiel, Yossi, Etgar, Lioz
• Format: Article
• Language: English
• Subjects: Anisotropy; chiral; Chirality; Dichroism; Electromagnetic radiation; Emission; Enantiomers; LED; Light emitting diodes; perovskite; Perovskites; Polarization; polarized emission; Quantum efficiency; Two dimensional analysis
• ISSN: 2195-1071; 2195-1071
• DOI: 10.1002/adom.202401205

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. For the first time, chiral 2D perovskite is embedded in a complete LED device, and the polarized emitted light from the sample is characterized. It is found that linear and circular polarized emission can be obtained from these chiral PeLED.