A layered hybrid perovskite belonging to the <110> series, (FA)2(HEA)2Pb2Br8 (HEA+, hydroxyethylammonium; FA+, formamidinium) exhibits a bright green narrow emission and a reversible mechanochromic luminescence effect: after grinding the powder a few seconds, the emission is blue shifted from 500 to 480 nm due to a partial amorphization. PeLEDs based on (FA)2(HEA)2Pb2Br8 as active material were also demonstrated, which is unprecedented for such a layered hybrid perovskite.

1D hybrid perovskites show RTP from the organic and LT phosphorescence from the inorganic layer by complex energy transfer processes.