Synthesis of pyridine-based push-pull chromophores via [2 + 2] cycloaddition-retroelectrocyclization and their p-doping performance in poly(3-hexylthiophene-2,5-diyl)

P-type doping is a widely adopted strategy to enhance the performance of organic semiconductors (OSCs), underscoring the importance and urgency of developing novel p-dopants. In this study, a series of pyridine-based cyano-acceptors were newly synthesized via a click-type [2 + 2] cycloaddition-retroelectrocyclization (CA-RE) reaction of aminopyridine-substituted alkynes with tetracyanoethylene (TCNE) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) under mild conditions. Their thermal stability, optical and electrochemical properties were characterized using thermogravimetric analysis (TGA), UV-vis spectroscopy, and cyclic voltammetry (CV). Furthermore, the p-doping performance of these cyano-rich acceptors, both before and after coordination with the Lewis acid tris(pentafluorophenyl)borane (BCF), was evaluated by photoelectron yield spectroscopy (PYS) and ultraviolet photoelectron spectroscopy (UPS). • A series of donor-acceptor-donor and donor-acceptor-acceptor type push-pull chromophores are synthesized via [2 + 2] cycloaddition-retroelectrocyclization reaction. • The first reduction potentials are effectively tuned by modifying the terminal substituents. • Lewis pairing with tris(pentafluorophenyl)borane enables the synthesized chromophores to function as effective p-dopants in poly(3-hexylthiophene-2,5-diyl).