Efficient mechanochromic- and electro-fluorescence from deep red to near-infrared region

In this work, we designed and synthesized a deep-red to NIR emissive donor-acceptor (D-A) material NZBPXZ. The non-doped OLED of NZBPXZ demonstrates NIR electro-luminescence (EL) at 744 nm with a maximum external quantum efficiency (EQEmax) of 0.96% with an exciton utilize efficiency (EUE) of 90%. Additionally, the crystalline of NZBPXZ underwent a large red-shift of 127 nm from 670 nm in visible light region to approximately 797 nm (with a PLQY of 7.7%) in NIR region upon mechanical grinding. This work not only enables efficient NIR electroluminescence in OLEDs, but also gives a new functional route for construction deep -red to NIR pure organic mechanochromic materials.