Properties of poly(3,4-ethylenedioxythiophene) ultrathin films detected by in situ electrochemical-surface plasmon field-enhanced photoluminescence spectroscopy

In this paper, we describe, for the first time, the combination of surface plasmon resonance spectroscopy (SPS) and surface plasmon enhanced photoluminescence spectroscopy (SPPL) with electrochemical techniques for the detection of photoluminescence in poly(3,4-ethylenedioxythiophene) (PEDOT) ultrathin films. The EC-SPS/SPPL technique allows for the recording of the weak photoluminescence from an ultrathin PEDOT film in its neutral state. A distinct photoluminescence switching was observed during the potential dependent doping/dedoping process. The EC-SPS/SPPL characterization results are consistent with the observed PEDOT bulk electrochromic properties obtained from UV−vis−NIR spectra. This suggests that the described combination method is capable of electrochemically controlling and optically detecting the very weak photoluminescence of ultrathin films.