Efficient Electron Injection from a Bilayer Cathode Consisting of Aluminum and Alcohol‐/Water‐Soluble Conjugated Polymers

A bilayer cathode consisting of aminoalkyl-substituted polyfluorene and Al layers (see Figure) effectively injects electrons into an electroluminescent polymer emitting layer. The alcohol- and water-soluble polyfluorene, and its quaternized salt, can be used to fabricate polymer light-emitting diodes with device performance comparable to, or exceeding, devices using Ba/Al cathodes.