Spin‐Lifetime Probe for Detecting Intramolecular Noncovalent Interaction in Organic Semiconductors

Intramolecular noncovalent interaction (INCI), a crucial strategy for effectively enhancing molecular planarity and extending π‐electron delocalization in organic semiconductors (OSCs), has played an increasingly important role in optoelectronic applications. However, though the INCI formation is regularly considered to improve the device performance by literature, there is no feasible approach to directly and reliably characterizing its formation in practical‐OSC films thus far. Here in this study, by theoretical analysis and calculation, the generation of INCIs in OSCs is found, normally consisting of relatively heavy elements, such as O···Se, O···S, N···S interactions, etc., can induce enhanced strength of spin‐orbit coupling, the primary factor dominating spin lifetime in OSCs. Based on this newly discovered theory, spin lifetime is creatively employed as a probe for sensitively detecting INCIs in OSC films via spin valves or field‐induced electron paramagnetic resonance, respectively. This study will highly promote academic and applicable developments of the cross‐cutting frontier research field between organic spintronics and electronics. Intramolecular noncovalent interactions boost the device performance in the optoelectronic field, but cannot be directly detected in organic semiconductor films thus far. Spin lifetime as a probe to detect intramolecular noncovalent interaction is innovatively used since it can influence the spin‐orbit coupling strength and thus modulate the spin lifetime. This work will significantly advance the interdisciplinary research of organic spintronics and electronics.