Toward Chiral Lasing from All-Solution-Processed Flexible Perovskite-Nanocrystal-Liquid-Crystal Membranes

Circularly polarized (CP) coherent light sources are of great potential for various advanced optical applications spanning displays/imaging to data processing/encryption and quantum communication. Here, the first demonstration of CP amplified spontaneous emission (ASE)/lasing from a free-standing and flexible membrane device is reported. The membrane device consists of perovskite nanocrystals (PNCs) and cholesteric liquid crystals (CLCs) layers sandwiched within a Fabry-Perot (F-P) cavity architecture. The chiral liquid crystal cavity enables the generation of CP light from the device. The device is completely solution-processable and displays CP ASE with record dissymmetry factor (glum) as high as 1.4, which is 3 orders of magnitude higher as compared with glum of CP luminescence of chiral ligand-capped colloidal PNCs. The device exhibits ultraflexibility as the ASE intensity remains unchanged after repeated 100 bending cycles and it is stable for more than 3 months with 80% of its original intensity. Furthermore, the ultraflexibility enables the generation of ASE from various objects of different geometric surfaces covered with the flexible perovskite membrane device. This work not only demonstrates the first CP ASE from a PNCs membrane with extremely high glum but also opens the door toward the fabrication of ultraflexible, extremely stable, and all solution-processable perovskite chiral laser devices. Chiral amplified spontaneous emission (ASE)/lasing from a free-standing membrane consisting of perovskite nanocrystals (PNCs) and cholesteric liquid crystals (CLCs) layers is demonstrated. Two CLCs layers with same helical structure act as reflectors to construct a Fabry-Perot cavity. The selective reflection of CLCs leads to polarization selectivity. The membrane device is highly flexible and all-solution-processable and exhibits a high dissymmetry factor of 1.4.image