Negative Charge Management to Make Fragile Bonds No Longer Fragile towards Electrons for Robust Organic Optoelectronic Materials

The development of robust organic (opto)electronic devices is mainly depressed by the poor intrinsic stability of organic materials on service. For organic light-emitting diode (OLED) materials, a key parameter for intrinsic stability is the bond-dissociation energy of the most fragile bond (BDE_f). Although rarely concerned, many OLED molecules have the lowest BDE_f in anionic states (BDE_f(−) ∼1.6−2.5 eV), which could be a fatal short-slab for device stability. Here, we confirmed the clear relationship between BDE_f(−), intrinsic material stability, and device lifetime, and further developed a general and effective strategy to promote BDE_f(−) ~1 eV for various fragile bonds by introducing appropriate negative charge manager within the molecule. The manager can firmly confine negative-charge and protect fragile bonds, which was verified in typical phosphine-oxide and carbazole derivatives, and backed by newly-designed molecules. This tactic provides a new perspective to reform the vulnerable building blocks for robust organic (opto)electronic materials and devices.