Hole Mobility Enhancement in Benzo[1,2‐b:4,5‐b']Dithiophene‐Based Conjugated Polymer Transistors through Directional Alignment, Perovskite Functionalization and Solid‐State Electrolyte Gating

Abstract

AbstractTunability in electronic and optical properties has been intensively explored for developing conjugated polymers and their applications in organic and perovskite‐based electronics. Particularly, the charge carrier mobility of conjugated polymer semiconductors has been deemed to be a vital figure‐of‐merit for achieving high‐performance organic field‐effect transistors (OFETs). In this study, the systematic hole carrier mobility improvement of benzo[1,2‐b:4,5‐b']dithiophene‐based conjugated polymer in perovskite‐functionalized organic transistors is demonstrated. In conventional OFETs with a poly(methyl methacrylate) (PMMA) gate dielectric, improvements in hole mobility of 0.019 cm2 V−1 s−1 are measured using an off‐center spin‐coating technique, which exceeds those of on‐center counterparts (0.22 ± 0.07 × 10−2 cm2 V−1 s−1). Furthermore, the mobility drastically increases by adopting solid‐state electrolyte gating, corresponding to 2.99 ± 1.03 cm2 V−1 s−1 for the control, and the best hole mobility is 8.03 cm2 V−1 s−1 (average ≈ 6.94 ± 0.59 cm2 V−1 s−1) for perovskite‐functionalized OFETs with a high current on/off ratio of >106. The achieved device performance would be attributed to the enhanced film crystallinity and charge carrier density in the hybrid perovskite‐functionalized organic transistor channel, resulting from the high‐capacitance electrolyte dielectric.