Boosting the Dopant Accommodation in Charge-Transfer Supramolecular Electrets Using Carbohydrate Block Copolymers in Phototransistor Memory

Abstract

Charge-transfer (CT)-based supramolecular systems have attracted considerable interest as electret materials for organic memory devices. However, uncontrolled dopant distribution, limited host–guest compatibility, and the formation of leakage pathways often compromise their morphological stability and memory performance. In this work, carbohydrate-based block copolymers (BCPs), maltotriose-block-poly(1-pyrenemethyl methacrylate) (PPy) and maltotriose-block-poly(benzyl methacrylate) (PB), are employed as supramolecular hosts for incorporating the electron acceptor F4-TCNQ, forming a series of supramolecular electret systems for organic phototransistor memory applications. Photoluminescence and time-resolved photoluminescence characterizations confirm efficient photoinduced intermolecular CT interactions in the PPy/F4-TCNQ systems, as evidenced by significant fluorescence quenching and a shortened excited-state lifetime. More importantly, solvent-vapor annealing induces supramolecular reorganization within the electret layer, thereby effectively regulating dopant distribution and reducing leakage pathways. Meanwhile, optical, morphological, and surface-energy analyses further reveal that the maltotriose carbohydrate block plays a critical role in suppressing channel interference and stabilizing the supramolecular architecture. As a result, the optimized phototransistor memory exhibits a high photosensitivity of 1.27 × 107 and a memory ratio of 1.61 × 106. Furthermore, reliable memory operation is maintained under low-light-intensity (0.01 mW cm–2) and low-operating-voltage (−0.1 V) conditions. These findings demonstrate that carbohydrate-based BCPs provide an effective platform for integrating CT supramolecular interactions with controllable dopant organization, offering a versatile molecular design strategy for developing high-performance organic photomemory devices.