Poly(ethylene imine) Impurities Induce n‐doping Reaction in Organic (Semi)Conductors

Abstract

Volatile impurities contained in polyethyleneimine (PEI), and identified as ethyleneimine dimers and trimers, are reported. These N‐based molecules show a strong reducing character, as demonstrated by the change in electrical conductivity of organic (semi)conductors exposed to the PEI vapor. The results prove that electron transfer rather than a dipole effect at the electrode interface is the origin of the work‐function modification by the PEI‐based layers.

Optical properties and conductivity of PEDOT:PSS films treated by polyethylenimine solution for organic solar cells

“…The reduction of T is associated to the A increase in this spectral region. The increase of the A band centered at 900 nm is associated with electron transfer to oxidized PEDOT chains from PEI, which also supports the conductivity reduction results [27,[30][31][32]. Fig.…”

Anion-induced N-doping of naphthalenediimide polymer semiconductor in organic thin-film transistors

“…11,12 Nevertheless a few stable n-type dopants have been reported via mechanisms other than integer charge transfer. [13][14][15][16][17][18][19][20][21][22][23][24][25] For example the addition of 1H-benzimidazole or benzimidazolium salts has succeeded in tuning of the work function of graphene and the conductivity of fullerene derivatives. 13,26 Mechanistic studies in the solution phase found that the dopant reacted with the fullerene derivative through hydride or hydrogen atom transfer to afford host radical anions, which were responsible for the doping effect.…”

Conductivity Enhancement of PEDOT:PSS Films via Phosphoric Acid Treatment for Flexible All-Plastic Solar Cells

“…Comparingwith the samples without PEI coating, the coating leads to the lower T which is attributed to the increase of A after the PEI coating even though the R is slightly reduced. PEI is a reduction reagent for PEDOT:PSS so that increases the A of the PEDOT:PSS films 34. Like the PEDOT:PSS films without PEI coating, the H 2 SO 4 -PEDOT:PSS films exhibit lower T than H 3 PO 4 -PEDOT:PSS films because of the higher R. Furthermore, a absorption band centered at 600 nm appears after PEI coating which is associated with transformation of positively charged PEDOT to neutral PEDOT,24 which also leads to the reduction of transmittance (Figure 3c) and electrical conductivity.…”