Preferred Acceptor-Domain Positioning via a Phase-Switched Bulk Heterojunction for Self-Powered Photodetector and Photovoltaic Applications

초록

In this study, a phase-switching process is introduced to a PM6:Y6-based active layer to implement a uniform surface with preferred Y6 acceptor-domain positioning and to minimize solution loss owing to the use of medium molds. By designing the process to fit the surface properties of a small-molecule Y6 acceptor-based bulk heterojunction, a sustainable and highly reproducible phase-switched active layer that can be formed at the desired location without wasting materials is successfully formed over an area of 2.25 cm2. It improved charge transport ability and suppressed surface defects owing to a molecular orientation favorable for efficient charge separation and transport. Furthermore, adding chloronaphthalene induced the domain growth of Y6 acceptors with dense molecular packing, which enhanced the effects of the phase-switching process. Uniformly distributed performance in the phase-switched active layer via the phase-switching process was demonstrated in fabricated large active-area devices. Furthermore, the process was utilized in a PM6:Y6-based self-powered photodetector, which improved detectivity owing to the suppression of the dark current density. Therefore, the phase-switching process is an important technology for forming high-quality thin films composed of small-molecule acceptors for efficient self-powered photodetector and photovoltaic applications. © 2023 American Chemical Society.

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