White Polymer Light-Emitting Electrochemical Cells Fabricated Using Energy Donor and Acceptor Fluorescent π-Conjugated Polymers Based on Concepts of Band-Structure Engineering

Abstract

The authors report on white polymer light-emitting electrochemical cells (PLECs) fabricated with a polymer blend film composed of a blue fluorescent π-conjugated polymer (blue FCP), poly(9,9-di-n-dodecylfluorenyl-2,7-diyl) (PFD), and a red-orange FCP, poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), based on concepts of band-structure engineering. Polymer blending is one of the simplest and most promising methods for fabrication of van der Waals interfaces, which convert electricity to light in PLECs. By optimizing the composition of PFD, MEH-PPV, poly(ethylene oxide) (PEO), and salt (KCF3SO3) in the active layer, white-light emission with Commission Internationale de l’Eclairage (CIE) coordinates of (x = 0.33, y = 0.31) can be achieved through light mixing of blue exciton emission from PFD and red-orange exciton emission from MEH-PPV at an applied voltage higher than the threshold voltage, Vthblue-FCP, which corresponds to Egblue-FCP/e, where Egblue-FCP is the band gap of PFD and e i...