π-stacked donor-acceptor molecule to realize hybridized local and charge-transfer excited state emission with multi-stimulus response

• The HLCT property based on the ISCT emitter is presented. • The HLCT&ISCT emitter enables multi-stimulus response properties. • High efficiency and exciton utilization in OLEDs are achieved. Organic materials with multi-stimulus response (MSR) properties have magnificent application prospects in the optoelectronics field. Herein, a new asymmetric donor-spiro-acceptor type hybridized local and charge-transfer excited state (HLCT) compound based on benzothiadiazole derivative (2P-BT) moiety, Spiro-2P-BT-TPA , was designed and synthesized. The fluorene unit has a rigid linker to position the acceptor and donor subunit in close vicinity with control over their spacing and molecular structure and to achieve MSR properties, such as quasi-aggregation-induced emission (quasi-AIE), mechanochromic and solvatochromic. Moreover, Spiro-2P-BT-TPA possesses a high photoluminescence quantum yield (PLQY) of 80.9% when it is incorporated in a solid matrix, owing to spatial confined D/A stacked structure, multi-inter/intramolecular interactions as well as quasi-AIE properties. OLEDs based on Spiro-2P-BT-TPA achieve an EQE of 6.6% and the exciton utilization is 40%. To the best of our knowledge, this is a novel example for HLCT materials based on intramolecular spatial charge transfer as well as MSR properties.