Related Experiment Video
Updated: Jan 29, 2026
Spray-Coated Melanin/PEDOT:PSS Films for Sustainable Organic Electrochemical Transistors
Published on: October 28, 2025
Ionic Liquids as Post-Treatment Agents for Simultaneous Improvement of Seebeck Coefficient and Electrical
Nitin Saxena1,2, Benjamin Pretzl1, Xaver Lamprecht1
1Lehrstuhl für Funktionelle Materialien, Physik-Department , Technische Universität München , James-Franck-Str. 1 , 85748 Garching , Germany.
Abstract:
Ionic liquid (IL) post-treatment for thin films of poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is employed for the simultaneous enhancement of Seebeck coefficients and electrical conductivities. Through systematic variation of the ILs, by changing the anions while keeping the cation unchanged, changes in thermoelectric, spectroscopic, and morphological properties are investigated by means of UV-vis spectroscopy and grazing-incidence wide-angle X-ray scattering (GIWAXS) as a function of the IL concentration. The simultaneous enhancement in the two important thermoelectric properties is ascribed to the binary nature of the ILs, which complements that of PEDOT:PSS. The anions of the ILs primarily interact with the positively charged, conducting PEDOT, while the cations interact with negatively charged insulating PSS. Therefore, post-treatment with ILs allows for primary and secondary doping of PEDOT:PSS at the same time. Differences in the obtained Seebeck coefficients for the investigated ILs are ascribed to the chemical properties of the anions. Additionally, the choice of the latter has implications on the morphology of the treated PEDOT:PSS films regarding average π-π-stacking distances of PEDOT chains, PEDOT-to-PSS ratios, and edge-on-to-face-on ratios, influencing charge transport properties macroscopically. A morphological model is presented, highlighting the influence of each IL in comparison with pristine PEDOT:PSS films.
Related Concept Videos
01:13Electrical Conductivity
In a practical conductor, an applied electric field may be sustained, causing a flow of electrons, which produce a current. The differential form of the current, the current density, is related to the electric field.
More generally, it is related to the force per unit charge, which involves the...
02:54Molecular and Ionic Solids
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
01:16Electric Field of Parallel Conducting Plates
Consider a cross-section of a thin, infinite conducting plate having a positive charge. For such a large thin plate, as the thickness of the plate tends to zero, the positive charges lie on the plate's two large faces. Without an external electric field, the...
03:10Ionic Radii
01:26Anticholinesterase Agents: Poisoning and Treatment
Irreversible agents form a strong bond with the cholinesterase enzyme, making it inactive. The breakdown of the phosphorylated enzyme is...
00:42Ionic Bonds
When atoms gain or lose electrons to achieve a more stable electron configuration they form ions. Ionic bonds are electrostatic attractions between ions with opposite charges. Ionic compounds are rigid and brittle when solid and may dissociate into their constituent ions in water. Covalent compounds, by contrast, remain intact unless a chemical reaction breaks them.
Opposing Charges Hold Ions Together in Ionic Compounds
Ionic bonds are reversible electrostatic interactions between ions...