The formation of polymer-dopant aggregates as a possible origin of limited doping efficiency at high dopant concentration

Julie Euvrard , Amélie Revaux (1) , Pierre-Alain Bayle (2) , Michel Bardet (2) , Dominique Vuillaume (3, 4) , Antoine Kahn

1 LPMC - Laboratoire de physique de la matière condensée
2 RM - Magnetic Resonance
3 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
4 NCM - IEMN - Nanostructures, nanoComponents & Molecules - IEMN

The polymer Poly[(4,8-bis-(2-ethylhexyloxy)-benzo(1,2-b:4,5-b’)dithiophene)-2,6-diyl-alt-(4-(2-ethylhexanoyl)- thieno[3,4-b]thiophene-)-2-6-diyl)] (PBDTTT-c) p-doped with the molecular dopant tris[1-(trifluoroethanoyl)-2- (trifluoromethyl)ethane-1,2-dithiolene] (Mo(tfd-COCF3)3) exhibits a decline in transport properties at high doping concentrations, which limits the performance attainable through organic semiconductor doping. Scanning Electron Microscopy is used to correlate the evolution of hole conductivity and hopping transport activation energy with the formation of aggregates in the layer. Transmission Electron Microscopy with energy-dispersive X-ray analysis along with liquid-state Nuclear Magnetic Resonance experiments are carried out to determine the composition of the aggregates. This study offers an explanation to the limited efficiency of doping at high dopant concentrations and reinforces the need to increase doping efficiency in order to be able to reduce the dopant concentration and not negatively affect conductivity.

Domaines: Chimie

Julie Euvrard, Amélie Revaux, Pierre-Alain Bayle, Michel Bardet, Dominique Vuillaume, et al.. The formation of polymer-dopant aggregates as a possible origin of limited doping efficiency at high dopant concentration. Organic Electronics, 2018, 53, pp.135-140. ⟨10.1016/j.orgel.2017.11.020⟩. ⟨hal-01939470⟩