Influence of Effective Mass on Carrier Concentration for PEDOT:PSS and S-PEDOT Thin Films Studied by Ellipsometry and Hall Measurement

Weherein investigate the optical anisotropy, carrierconcentration,and carrier mobility in the transparent conductive polymer poly(3,4-ethylendioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and self-doped PEDOT (S-PEDOT) using spectroscopicellipsometry and Hall measurements in the van der Pauw configuration.The influence of the effective mass on the electrical carrier concentrationsand mobility is demonstrated in PEDOT:PSS and S-PEDOT thin films withdifferent carrier concentrations. The optical carrier concentrationdetermined by ellipsometry and Hall measurements in both PEDOT:PSSand S-PEDOT shows good agreement in a collinear relationship by consideringthe variation of effective mass. Conversely, the electron mobilityvalues obtained from spectroscopic ellipsometry and Hall measurementsexhibit rather poor agreement. These findings are thought to originatefrom the grain boundaries at between PEDOT nanocrystals.