Recent advances in conjugated polyelectrolytes for emerging optoelectronic applications

This review summarizes recent advances in the science and applications of conjugated polyelectrolytes (CPEs), with an emphasis on direct visual sensing, cellular imaging, and the fabrication of optoelectronic devices. CPEs backbones that incorporate donor-acceptor units are useful for direct visual sensing, whereas CPEs with hyperbranched structures, or biocompatible long side chains, are particularly useful for cellular imaging. With specially designed counterions, CPEs also demonstrate unique function in device fabrication and operation, for example, in dye-sensitized solar cells (DSSCs), bulk heterojunction (BHJ) solar cells, polymer light-emitting diodes (PLEDs), polymer light-emitting electrochemical cells (PLECs), and organic thin film transistors (OFET). Additionally, new strategies to modify and optimize CPE properties for specific applications are provided. The work summarized herein not only illustrates relationships between molecular structures and function, but also highlights how the structural versatility of CPEs makes them a unique category of multifunctional materials with the potential for fulfilling a variety of optical and electronic applications in solution, mixed media, and in the solid state.