Achieving high-performance non-doped sky-blue OLEDs with negligible efficiency roll-off by combining AIE, HLCT and mechanoluminescence features

The hot exciton materials with high-lying reverse intersystem crossing provide great potential for the realization of efficient, low-cost and stable organic light-emitting diodes (OLEDs). However, it is highly desired but still challenging to achieve high-performance non-doped blue OLEDs with hot exciton luminogens. In this work, a new hybridized local and charge transfer (HLCT) luminogen 2-(4-(2-(4-(1,2,2-triphenylvinyl)phenyl)-1H-phenanthro[9,10-d]imidazole-1-yl)phenyl)phenanthro[9,10-d]oxazole (abbreviated as TPE-PI-PO) with the incorporation of tetraphenylethylene is obtained for constructing the high-performance non-doped blue OLEDs. TPE-PI-PO possesses the multifunctional features of aggregation-induced emission (AIE), HLCT and mechanoluminescence with high photoluminescence quantum yield (58%) in the neat film. The non-doped OLEDs based on TPE-PI-PO exhibits sky-blue emission, high luminance of 13,020 cd m−2 and the maximum efficiencies of 11.62 cd A−1, 5.08% with the negligible efficiency roll-off as low as 1.6% at 1000 cd m−2. The electroluminescent performance is highly competitive with the best reported non-doped blue fluorescent OLEDs based on AIE luminogens. These results can shed light on a feasible design principle to develop high-quality HLCT-type luminogens for high-performance non-doped blue OLEDs.