Three malononitrile based D-A-D compounds with TPA, PhCz and DMAC donor (DPMM-2TPA, DPMM-2PhCz and DPMM-2DMAC) at the para-position of phenyl group on the DPMM unit are synthesized and their photophysical properties are systematically investigated. All compounds display positive solvatochromic behaviour, good thermal and electrochemical stability. Moreover, pronounced aggregation-induced emission and mechanochromic luminescence are observed in their solid states. DPMM-2TPA and DPMM-2DMAC realized red fluorescence, extremely small ΔE_ST of 0.06 and 0.01 eV and significant thermally activated delayed fluorescence character, due to the operative RISC process via spin orbit coupling from ³LE to ¹CT and hyperfine coupling between ³CT and ¹CT, respectively. Nevertheless, TADF cannot be detected for DPMM-2PhCz because of its large ¹CT and ³CT gap (0.34 eV) and inaccessible endothermic energy transfer. These results suggest that the energy level of ¹CT, ³LE and ³CT is adjustable by carefully designing the molecular configuration and thus enable the emission switch from non-TADF to TADF. Multilayer OLEDs based on DPMM-2TPA and DPMM-2DMAC exhibit a maximum EQE of 16.5% and 12.7%, respectively, which is 3–4 times higher than DPMM-2PhCz based non-TADF OLEDs (EQE = 4.4%).

合成了在TPMM单元上苯基对位的，具有TPA，PhCz和DMAC供体的三种基于丙二腈的DAD化合物（DPMM-2TPA，DPMM-2PhCz和DPMM-2DMAC），并系统地研究了它们的光物理性质。所有化合物均表现出正溶剂溶变色行为，良好的热稳定性和电化学稳定性。此外，在其固态下观察到明显的聚集诱导的发射和机械致变色发光。DPMM-2TPA和DPMM-2DMAC实现红色荧光，极小ΔE _ST的0.06和0.01 eV和显著热活化延迟荧光性质，由于经由自旋轨道耦合从手术过程RISC ³ LE至¹ CT和超精细耦合之间³ CT和¹ CT。但是，由于DPMM-2PhCz的¹ CT和³ CT间隙（0.34 eV）大且吸热能量传递难以到达，因此无法检测到TADF 。这些结果表明，通过仔细设计分子构型可以调节¹ CT，³ LE和³ CT的能级，从而实现从非TADF到TADF的发射切换。基于DPMM-2TPA和DPMM-2DMAC的多层OLED的最大EQE分别为16.5％和12.7％，这比基于DPMM-2PhCz的非TADF OLED（EQE = 4.4％）高3-4倍。