KIP publications

year 2013
author(s) Tobias Glaser, Sebastian Beck, Bernd Lunkenheimer, Daniela Donhauser, Andreas Köhn, Michael Kröger, Annemarie Pucci
title Infrared study of the MoO3 doping efficiency in 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP)
KIP-Nummer HD-KIP 13-06
KIP-Gruppe(n) F6
document type Paper
Keywords Electrochemical doping; Doping efficiency; Charge transfer; Charge dissociation; Agglomeration; Infrared spectroscopy
source Organic Electronics 14 (2013) 575-583
Abstract (en)

Electrochemical doping produces clear changes in the vibrational spectra of organic semiconductors as we show here for the system molybdenum oxide (MoO3) doped into the charge transport material 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP). Based on density functional theory (DFT) calculations of vibrational spectra, the new spectral features can be attributed to the CBP cation that forms as a result of electron transfer from CBP to MoO3. The intensity of the new vibrational lines is a direct measure for the probability of charge transfer. MoO3 agglomerating within the CBP matrix limits the active interface area between the two species. The appearance of a broad electronic transition in the infrared range indicates a new electronic structure at the interface compared to the individual components. The intensity of this electronic excitation serves as a measure for the interface area indicating a linear increase with MoO3 concentration. Deposition onto cooled substrates results in smaller agglomerates, and thus yields a higher efficiency.

  author   = {Glaser, Tobias and Beck, Sebastian and Lunkenheimer, Bernd and Donhauser, Daniela and K\"{o}hn, Andreas and Kr\"{o}ger, Michael and Pucci, Annemarie},
  title    = {Infrared study of the {Mo}{O}$_3$ doping efficiency in 4,4'-bis({N}-carbazolyl)-1,1'-biphenyl ({CBP})},
  journal  = {Organic Electronics},
  year     = {2013},
  volume   = {14},
  number   = {2},
  pages    = {575 - 583},
  doi      = {10.1016/j.orgel.2012.11.031},
  url      = {}
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