chemistry

PEDOT:PSS

PEDOT:PSS is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand PEDOT:PSS rather than just read about it. In short: Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is a composite material where PEDOT (the conductive polymer) provides electrical conductivity, and PSS (polystyrene sulfonate) acts as a counter-ion to balance the charge and improve the water solubility and processability of PEDOT. Polystyrene sulfonate is a sulfonated polystyrene.

Key takeaways

PEDOT:PSS belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect PEDOT:PSS to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of PEDOT:PSS from memory before moving on to harder problems.

Reference excerpt

Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is a composite material where PEDOT (the conductive polymer) provides electrical conductivity, and PSS (polystyrene sulfonate) acts as a counter-ion to balance the charge and improve the water solubility and processability of PEDOT. Polystyrene sulfonate is a sulfonated polystyrene. Part of the sulfonyl groups are deprotonated and carry a negative charge. The other component poly(3,4-ethylenedioxythiophene) (PEDOT) is a conjugated polymer and carries positive charges and is based on polythiophene. Together the charged macromolecules form a macromolecular salt.

Synthesis PEDOT:PSS can be prepared by mixing an aqueous solution of PSS with EDOT monomer, and to the resulting mixture, a solution of sodium persulfate and ferric sulfate. The addition of these reagents initiates the oxidative chemical polymerization of EDOT in water to form PEDOT. The stabilizing PSS forms a shell around a core of PEDOT in a nano-sized structure. The negatively charged sulfonic acid ions help stabilize the positively charged PEDOT ions.

Applications PEDOT:PSS has the highest efficiency among conductive organic thermoelectric materials (ZT~0.42) and thus can be used in flexible thermoelectric generators. Yet its largest application is as a transparent, conductive polymer with high ductility. For example, AGFA coats 200 million photographic films per year with a thin, extensively-stretched layer of virtually transparent and colorless PEDOT:PSS as an antistatic agent to prevent electrostatic discharges during production and normal film use, independent of humidity conditions, and as electrolyte in polymer electrolytic capacitors. PEDOT:PSS is commonly used in organic light emitting diode (OLED) and organic solar cell for hole injection or hole extraction to improve carrier transport. If organic compounds, including high boiling solvents like methylpyrrolidone, dimethyl sulfoxide, sorbitol, ionic liquids and surfactants, are added conductivity increases by many orders of magnitude. This makes it also suitable as a transparent electrode, for example in touchscreens, organic light-emitting diodes, flexible organic solar cells and electronic paper to replace the traditionally used indium tin oxide (ITO). Owing to the high conductivity (up to 4600 S/cm), it can be used as a cathode material in capacitors replacing manganese dioxide or liquid electrolytes. It is also used in organic electrochemical transistors. The conductivity of PEDOT:PSS can also be significantly improved by a post-treatment with various compounds, such as ethylene glycol, dimethyl sulfoxide (DMSO), salts, zwitterions, cosolvents, acids, alcohols, phenol, geminal diols and amphiphilic fluoro-compounds. This conductivity is comparable to that of ITO, the popular transparent electrode material, and it can triple that of ITO after a network of carbon nanotubes and silver nanowires is embedded into PEDOT:PSS and used for flexible organic devices. PEDOT:PSS is generally applied as a dispersion of gelled particles in water. A conductive layer on glass is obtained by spreading a layer of the dispersion on the surface usually by spin coating and driving out the water by heat. Special PEDOT:PSS inks and formulations were developed for different coating and printing processes. Water-based PEDOT:PSS inks are mainly used in slot die coating, flexography, rotogravure and inkjet printing. If a high viscous paste and slow drying is required like in screen-printing processes PEDOT:PSS can also be supplied in high boiling solvents like propanediol. Dry PEDOT:PSS pellets can be produced with a freeze drying method which are redispersable in water and different solvents, for example ethanol to increase drying speed during printing. Finally, to overcome degradation to ultraviolet light and high temperature or humidity conditions PEDOT:PSS UV-stabilizers are available. Linköping University claim to have made a "wooden transistor" by replacing the lignin from balsawood with PEDOT:PSS

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with PEDOT:PSS

Start with the simplest possible case. Write down what PEDOT:PSS claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to PEDOT:PSS before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about PEDOT:PSS ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of PEDOT:PSS

In research: PEDOT:PSS appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses PEDOT:PSS in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: PEDOT:PSS is common in secondary-school and first-year university syllabi. It links to neighbouring topics Antistatic agents, Conductive polymers, Copolymers, so understanding it makes those chapters shorter.
In everyday life: Look for PEDOT:PSS outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “PEDOT:PSS” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study PEDOT:PSS in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PEDOT:PSS means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain PEDOT:PSS out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PEDOT:PSS in simple terms?

Why does PEDOT:PSS matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study PEDOT:PSS?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on PEDOT:PSS.