Naphthalimide-Based 3D Organic Semiconductors: Synthesis and Application as Photo-electrocatalysts for Organic Dyes Degradation and Water Splitting

Abstract

1,2-diketone-based naphthalimide has emerged as an important electron-withdrawing building block in the synthesis of organic semiconductor assemblies for a wide range of applications. The reaction with different diamine derivatives enables the formation of pyrazine linkers which promotes planarity and rigidity of the naphthalimide-based semiconductors, therefore tunning their electronic structure and processability. Despite the significant use of this versatile building block to generate flat and rigid assemblies, the correlation between rigidity and dimensionality in these systems and their photocatalytic activity remains unexplored so far. Herein, with the aim to modulate the photocatalytic activity of these materials, we have developed a new family of assemblies with different dimensionality end-capped with naphthalimide moieties in which one (NIPB), three (3NIPT) and four (4NIPTM) units have been selectively introduced. The good processability of these novel semiconductors combined with their suitable energy levels allowed their application as photo-electrocatalysts for the degradation of organic dyes and for water splitting. The derivative with the highest dimensionality, 4NIPTM, showed higher photo-electrocatalytic activity and lower charge transfer resistance than that of conventional semiconductors (such as TiO2 and C3N4), reaching photocurrents up to 20 mA cm-2.