Single-Step PEDOT deposition by oxidative chemical vapor deposition for opto-electronic applications

Herein, we have developed a tubular hot wall oCVD reactor, using EDOT as monomer and SbCl5 as oxidant (Figure 1a). Seven glass (B, D, E, and F) and silicon (A, C, and G) substrates are placed all along the reactor length (Figure 1b). Further, we have extensively investigated the influence of some key deposition conditions (substrate temperature and coating time) on the deposit morphology, structure, chemical composition, and deposition rate and on their optical transparency and electrical conductivity. Among the numerous results obtained, it can be emphasized that deposition rates are uniform along the reactor length for specific temperatures. The electrical conductivity is spatially uniform for all the temperatures tested. These findings correlate with an in-depth analysis of the film structure and composition, in particular with XRD results demonstrating a strong face-on orientation of the films, corresponding to the quinoid conductive form of PEDOT. FTIR spectra confirm the presence of a quinoid structure related the C=C asymmetric stretching vibration at ~ 1520 cm -1 and a successful polymerization of intact EDOT monomer units. This paves the way for improving the intrinsic properties of PEDOT thin films allowing efficient integration into next-generation solar cells and OLED devices.