Strong Near-Infrared Solid Emission and Enhanced N-Type Mobility for Poly(naphthalene Diimide) Vinylene by a Random Polymerization Strategy

Organic semiconductors possessing both strong solid emission and charge transport ability are crucial for certain applications such as organic light-emitting transistors and injection lasers, yet they are rather rare. Among those which are successful, n-type materials with long emission wavelength are even more scarce. In this work, a series of random polymers with the dithiophene unit into a poly(naphthalene diimide) vinylene are synthesized. A strong near-infrared solid emission under wavelength of 730 nm and photoluminescence efficiency of 11.2% is achieved, with an enhanced n-type OFET performance of electron mobility up to 0.011 cm² V^-1 s^-1. GIXRD and AFM analysis reveal that the introduction with confined dithiophene can improve the localized Ï-πintermolecular interaction, while retaining the overall low crystalline state for thin films of these polymers, which should be the critical factor for balancing the solid emission and charge transport ability. This simple random polymerization strategy might be beneficial in future molecular design for such dual functional materials.