Pinacolborane (Bpin) is a functional group used exclusively as a reactive site in the Suzuki-Miyaura cross-coupling reaction. In this work, we elucidated an unprecedented effect of the Bpin group in a p-type organic semiconducting molecule on the ionization potential of its crystal surface. The aligned Bpin groups on the crystal surface, oriented toward air, collectively generate a large surface dipole moment, which shifts the vacuum level downward and results in spontaneous hole generation via air oxidation.
