A single-step treatment with bio-based green solvents can raise the electrical conductivity of the conducting polymer PEDOT:PSS by more than 2,000 times, according to a peer-reviewed study published in Discover Materials. The approach replaces the toxic, corrosive acids conventionally used to enhance the polymer’s conductivity and brings acid-free, indium tin oxide (ITO)-free transparent electrodes for organic solar cells a step closer.
PEDOT:PSS, a blend of the conducting PEDOT chain and the insulating PSS polymer, is a workhorse material for solution-processed transparent electrodes. Its as-prepared conductivity, however, is modest: the researchers measured 0.41 siemens per centimetre for pristine films. Conventional conductivity-enhancement strategies rely heavily on hazardous acids, which pose environmental and processing risks, and despite extensive work with polar solvents and additives, achieving high conductivity through environmentally benign materials in a single step has remained a challenge.
The team pre-treated aqueous PEDOT:PSS dispersions with three bio-based green solvents: ethanol, cyrene, and isoamyl alcohol. Ethanol proved the most effective, lifting conductivity to 823.5 S/cm. Cyrene followed at 602.7 S/cm, while isoamyl alcohol reached 135.2 S/cm. All three dramatically outperformed the untreated material while eliminating the need for hazardous acids entirely.
The underlying mechanism, the authors report, involves effective diffusion of the green solvents into the PEDOT:PSS complex. This enables charge screening that weakens the Coulombic interactions between the conducting PEDOT chains and the insulating PSS chains. Phase separation follows, and excess insulating PSS is selectively removed from the film surface, leaving behind a more conductive network.
Structural analyses corroborated this picture. Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, and atomic force microscopy all confirmed the formation of extended quinoid PEDOT conformations, enhanced crystallinity, and larger conductive domains in the treated films. These structural changes are consistent with the observed conductivity gains.
The practical performance of the treated films was assessed using a standard figure of merit for transparent electrodes, the ratio of direct-current conductivity to optical conductivity. Ethanol-treated films achieved a value of 36 at a wavelength of 550 nanometres, which the authors describe as competitive with ITO for transparent electrode applications.
To test the material in a working device, the researchers used the green solvent-treated PEDOT:PSS as the anode in organic solar cells. The treated films delivered a power conversion efficiency of 1.86 percent, an improvement of more than 30-fold over devices built on pristine PEDOT:PSS.
The study frames the result as a sustainable, non-toxic, acid-free pathway to PEDOT:PSS-based electrodes for eco-friendly ITO-free organic photovoltaics and flexible optoelectronic devices.
The work also addresses a broader sustainability tension in organic electronics.
The article was published open access on 22 October 2026 and is currently shared as a peer-reviewed, accepted manuscript that carries a permanent DOI; the authors note this version remains subject to further editorial edits before the final Version of Record replaces it. The research team included Zakariya Zubair, Mohamad Adzhar Md Zawawi, Muhammad Qamar Khan, Muhammad Zeshan Ali, and Ick Soo Kim.
Subject of Research: Enhancing PEDOT:PSS conductivity with bio-based green solvents for ITO-free organic solar cell electrodes
Article Title: Enhancing the conductivity of PEDOT PSS conducting polymer using green solvent for indium tin oxide free organic solar cells
Article References: Zubair, Z., Zawawi, M. A. M., Khan, M. Q., Ali, M. Z., & Kim, I. S. (2026). Enhancing the conductivity of PEDOT PSS conducting polymer using green solvent for indium tin oxide free organic solar cells. Discover Materials. https://doi.org/10.1007/s43939-026-01037-z
Image Credits: AI Generated
DOI: 10.1007/s43939-026-01037-z
Keywords: PEDOT:PSS, green solvents, organic solar cells, transparent electrodes, ITO-free, conductivity, ethanol, cyrene, flexible electronics, organic photovoltaics, Enhancing, PEDOT
News Source: Denise Maddox. (October 29, 2026). Green Solvents Boost PEDOT:PSS Conductivity 2,000-Fold for ITO-Free Solar Cells. Scienmag.
