Emerging Doping Paradigms in Organic Semiconductors

Abstract

Efficient and controllable doping is an indispensable requirement for modulating charge carrier density, optimizing interfacial charge injection, and enabling high-performance organic optoelectronic, thermoelectric, and bioelectronic devices. While conventional doping strategies have historically relied on direct redox-reaction chemistry governed by strict frontier molecular orbital alignment, the field has recently transitioned toward a multimechanism paradigm. In this Perspective, we critically evaluate emerging doping mechanisms that bypass traditional thermodynamic and morphological limitations, focusing on ion-exchange, catalytic activation, electrophilic and nucleophilic attacks, and deprotonation-induced pathways. We establish a comprehensive physical chemistry framework comparing these strategies, demonstrating how local chemical transformations and covalent-mediated pathways not only expand the library of dopable organic semiconductors but also offer profound physical-chemical advantages including superior doping efficiency, enhanced host-dopant miscibility, and exceptional environmental stability. Finally, we outline the key challenges and future milestones required to transition these highly efficient doping protocols into practical industrial technologies, highlighting the urgent need for precise spatial patterning, long-term operational and environmental stabilization under real-world stress, and the translation of efficient doping to advanced functional devices.