Naphthyridinedione-based multifunctional small molecules for applications in both photovoltaics and transistors

Abstract

We report multifunctional organic semiconductor materials for both organic photovoltaics (OPVs) and organic field-effect transistors (OFETs) based on a novel bis-lactam core, 1,5-naphthyridine-2,6-dione (NTD). Two different NTD derivatives, NTDC-N and NTDC-N-4F, are designed and synthesized to investigate the effects of π-conjugation extension and fluorination of an end group on molecular properties and optoelectronic device performance. Grazing-incidence wide-angle X-ray scattering (GIWAXS) results confirm that the two molecules are face-on oriented with compact stacking which is favorable for OPV applications. Under optimum conditions, OPVs based on NTDC-N and NTDC-N-4F as acceptor materials exhibit PCEs of 7.5% and 8.2%, respectively, with PCE-10 as the donor material. Atomic force microscopy (AFM) images illustrate a smoother surface morphology for NTDC-N-4F compared to that for NTDC-N, which contributes to better performance. In addition, OFET applications of NTDC-N and NTDC-N-4F show decent ambipolar mobilities of 10⁻³–10⁻² cm² V⁻¹ s⁻¹. These results demonstrate that NTD can be applied in numerous different optoelectronic devices for multiple purposes as a versatile organic semiconducting building block depending on its molecular design strategies.