Imaging the structure of the p‐n junction in polymer light‐emitting electrochemical cells

Light‐emitting electrochemical cells (LECs) offer a new approach to light‐emitting devices fabricated from semiconducting polymers. The p‐n junction formed in situ in an LEC through electrochemical doping has been imaged in the surface cell configuration by measuring the doping profile, the electric field profile within the junction, and the electroluminescence emission profile. The methods used are described and the results interpreted to provide a detailed picture of the structure of the p‐n junction.