Doping distribution of an operating organic light-emitting diode: a raman map analysis

摘要

We present confocal Raman spectroscopy (CSRS) maps of Poly(9,9-dioctylfluorene) (PFO)-based organic light emitting diode under operation. The CSRS analysis of the OLEDs was performed in normal room conditions. The non-emissive spots presented higher Raman intensity and broadening of the vibrational bands in comparison with the luminescent ones. The phenomenon is associated with an increase in the PFO - * absorption band and hence modification of the PFO doping which becomes favorable to the excitation wavelength, thus the Raman spectrum is enhanced. To the authors’ knowledge this image technique had been missed for the OLED technology.