High-efficiency synthesis of a naphthalene-diimide-based conjugated polymer using continuous flow technology for organic field-effect transistors

Abstract

A conjugated polymer based on naphthalene-diimide and dithiophene units was synthesized by continuous flow synthesis. Due to the large specific surface area and excellent heat transfer, the polymerization was completed within ∼35 min at 110 °C. Compared to flask synthesis, the continuous flow technology exhibited a high synthesis efficiency and significant reduction in reaction times. The polymer using flow synthesis exhibited higher molecular weight (17.28/35.27 vs. 4.86/13.21 kg mol⁻¹), lower polydispersity indexes (2.0 vs. 2.7), and a more ordered crystalline structure. Consequently, much higher electron mobilities (0.74 vs. 0.11 cm² V⁻¹ s⁻¹) with I_on/I_off ratios of 10⁶ were obtained for the polymer using flow synthesis. This study demonstrates that continuous flow synthesis will be promising in the preparation of conjugated polymers with high efficiency.