Engineering aromatic heterocycle strategy: Improving copper electrodeposition performance via tuning the bandgap of diketopyrrolopyrrole-based leveler

The bandgap of organics is an important descriptor to evaluate the interface adhesion of an organic agent on metal surface. However, insight into the role of chalcogens tuning of pi-conjugated materials in influencing the bandgap is still deficient. Here, a family of diketopyrrolopyrrole(DPP)-based quaternary ammonium salts containing different chalcogens are innovatively synthesized through bottom-up strategy and served as new levelers in conformal copper electrodeposition. The photophysical and electrochemical properties including cyclic voltammetry (CV),potentiodynamic polarization curves and galvanostatic measurements (GMs) of those compounds were tested. Compared with other counterparts, SeDPP-QAS presents the narrowest bandgap showing great potential in conformal copper electrodeposition. Through-hole electroplating test and the scanning electron microscope (SEM) images of coating layer demonstrate that bandgap tuning is an efficient method to level and regulate the electrodeposition performance. Besides, theoretical calculations and X-ray photoelectron spectroscopy (XPS) were applied detect the adsorption mechanism between organic agent and copper surface. This work broadens the understanding of bandgap engineering of organics in copper electrodeposition, and provides guidance for the future design of organic materials in adsorbing other metal-based materials. (C) 2019 Elsevier Ltd. All rights reserved.