Exciton‐Scissoring Perfluoroarenes Trigger Photomultiplication in Full Color Organic Image Sensors

Abstract

We report an unprecedented but useful functionality of perfluoroarenes to enable exciton scissoring in photomultiplication-type organic photodiodes (PM-OPDs). Perfluoroarenes that are covalently connected to polymer donors via photochemical reaction enable us to demonstrate high external quantum efficiency and B-/G-/R-selective PM-OPDs without the use of conventional acceptor molecules. We investigated the operation mechanism of the suggested perfluoroarene-driven PM-OPDs, “How can covalently bonded polymer donor:perfluoroarene PM-OPDs perform as effectively as polymer donor:fullerene blend-based PM-OPDs?”. By employing a series of arenes and conducting steady-state/time-resolved photoluminescence and transient absorption spectroscopy analyses, we find that interfacial band bending between the perfluoroaryl group and polymer donor is responsible for exciton scissoring and subsequent electron trapping, which induces photomultiplication. Owing to the acceptor-free and covalently interconnected photoactive layer in the suggested PM-OPDs, superior operational and thermal stabilities were observed. Finally, we demonstrated finely patterned B-/G-/R-selective PM-OPD arrays that enable the construction of highly sensitive passive matrix-type organic image sensors.