Electronic properties at gold/conjugated-polyelectrolyte interfaces

The electronic structure of neutral conjugated polymer and conjugated polyelectrolytes (CPE) was investigated using X-ray (XPS) and UV photoelectron spectroscopy (UPS). Control of film thickness was done by changing spin-casting speed and the solution concentration. Spin coating from a suitable solvent and an appropriate spin speed was selected for the deposition of polymers. Atomic force microscopy (AFM) and XPS were used to determine the film thickness, while molecular orbital alignment and band bending at the interface were determined using XPS and UPS spectra. XPS spectra showed the absence of chemical bond formation between the CPEs and the Au surfaces. The study opened new opportunities to understand the function of these materials in PLEDs, device performance, and the design of new materials for polymer-based optoelectronic devices.