N-type conjugated polymer semiconductor materials based on Aza-BODIPY dye with Naphthodipyrrolopyrrole (NDP-AB)

Abstract

So far, the charge carrier mobility as well as the stability of n-type semiconductors fall behind when compared to the p-type ones. Therefore, exploring high-performance n-type semiconductor materials plays a crucial role in the further development of organic field-effect transistors (OFETs) for industrial applications. Naphthodipyrrolopyrrole-based dimeric aza-boron dipyrromethene dyes (NDP-AB) present strong electron-deficient units, which are rarely investigated. In this work, the NDP-AB chromophore is, for the first time, introduced as the acceptor in donor-acceptor type polymers. The results show that the NDP-AB based polymers exhibit extra-low LUMO energy levels, which endow the semiconductor layer with the ability to form Ohmic contacts with electrodes. This is advantageous for electron injection. In addition, the polymers present not only a strong aggregation as well as short π-π stacking d-spacing, but also a good planar polymer backbone and strong ICT effect. That phenomenon is advantage for the electron carrier transport across the adjacent molecules and the individual molecule. As a consequence, the NDP-AB-based polymers exhibit n-type behavior with electron transport mobility up to 0.89 cm2 V−1 s−1. This work demonstrate that NDP-AB is a promising electron-deficient building block for high-performance n-type semiconductors.