A new understanding of electron affinity of –OCH3 substituent groups based on single molecular conductance

Abstract To employ substituent groups to modulate the electronic properties of organic molecules as predicted, learning about their electron affinity is an important prerequisite. Herein, we used conventional electron-donating / withdrawing (ED/EW) substituent groups -OMe/ COOMe to modify TB, finding the resulting molecules OTB and CTB both demonstrated lower molecular conductance than TB. Current-voltage modeling and DFT calculation reveal -OCH3 demonstrated EW features instead of ED characteristics, which was supported by energy gap simulation and light emission as pulsed 365 nm light. This phenomenon was rarely observed, highlighting the importance of substituent groups’ electron affinity investigation in conductance based organic electronics.