Polydopamine-coated gold nanoparticles used as modifier of the electron transport layer for PTB7:PC71BM polymer solar cells

Polydopamine (PDA)-coated gold nanoparticles (Au@PDA) were used as electronic transport layer (ETL) modifiers in PTB7:PC71BM polymer solar cells. PDA can effectively modify the surface of gold nanoparticles (Au NPs) and improve the stability of them. In addition, PDA also effectively binds to ZnO ETL, reducing surface defect and improving the combination between the interface layer and the active layer. In this study, AuNPs with particle size of about 30 nm was prepared by Frens reduction method, and then the dopamine (DA) self-polymerized on the surface of them to obtain a core–shell structural material Au@PDA. By regulating the polymerization time of DA, different PDA shell thickness was obtained. The Au@PDA was introduced into ZnO ETL to generate local plasmon resonance adsorption. When dopamine polymerized for an hour, the short current density of the modified solar cells reached 13.98 mA/cm 2 , and the power conversion efficiency reached 6.03%, which was 130% of the device without Au@PDA.