Anthracene- and Thiophene-containing MEH-PPE-PPVs: Synthesis and Study of the Effect of the Aromatic Ring Position and the Sidechain Density on the Photophysical Properties and Photovoltaic Performance

摘要

The possibility of chemically manipulating the material properties of polymers combined with a variety of easy and cheap processing techniques has made polymer-based materials present in almost every aspect of modern society. Organic semiconductors have several advantages, compared to classical ones: (a) low cost synthesis, and (b) easy manufacture of thin film devices by vacuum evaporation/sublimation, solution cast or printing technologies. The electronic band gap of organic semiconductors can be engineered by chemical synthesis for simple color tuning in light emitting diodes (LEDs) and for improvement of the performance of organic solar cells.1 Therefore, it is important to investigate possibilities to tune the band gap of conjugated polymers. Various methods of band gap tuning have been described.1 In this work we describe the synthesis and characterization of three thiophene- (P1-P3) and two anthracene- containing PPE-PPVs (P4, P5). Thereby, we investigate the influence of thiophene and anthracene, respectively, and their position in the polymeric backbone on the tuning of the backbone planarity and, consequently, the bandgap of the systems. Furthermore, we have evaluated the photovoltaic performance of P1-P5 as donor materials with respect to (1) the position of either thiophene or anthracene within the conjugated backbone and (2) the density of the hydrophobic side chain shell around the conjugated backbone.