Background and Originality Content
Stability against oxygen is of great importance in the practical applications of organic semiconductor materials, considering the functional groups with high photoelectric activity are particularly sensitive to oxygen when excited by light and electricity.[1-2] The adverse effects of unstable organic semiconductors as shortened service lifetime, deteriorative mechanical property and optoelectronic performance are ubiquitous in various single-molecular and hybrid systems which must work under ambient conditions, including integrated photovoltaic,[3-4] fluorescence imaging,[5-7] organic light emitting diode (OLED),[8] and organic field-effect transistors (OFET).[9] To inhibit the degradation, several kinds of additives such as light screeners/absorbers, excited-state quenchers, antioxidants, radical scavengers have been developed according to different stabilization mechanisms. Whereas for organic semiconductors, the purity requirements are very severe to avoid the low efficiency owing to the defect role of additive molecules. Besides, customization of the molecular structures was proved effective for the enhancement of stability, like replacing the covalent bonds with low bond dissociation energy,[10] adding electron withdrawing groups to increase the oxidation potentials[11] and so on. However, in many cases the molecular design of electronic structure is not enough to meet the functional and stability requirements at the same time.