pedot

PEDOT stands for poly(3,4-ethylenedioxythiophene), a conducting polymer in which the conjugated polymer backbone allows charge transport. The polymer is most commonly used in the form of PEDOT with polystyrene sulfonate as a dopant, forming PEDOT:PSS. The PSS component makes the material dispersible in water, enabling solution processing and facile thin-film formation.

Synthesis and processing of PEDOT typically involve oxidative polymerization of the monomer EDOT (3,4-ethylenedioxythiophene) using chemical oxidants. In many formulations, PSS is added during polymerization to provide counterions and processing stability. Films are deposited by spin-coating, drop-casting, or printing and can be further treated with high-boiling solvents (such as dimethyl sulfoxide, ethylene glycol, or sorbitol) to enhance phase separation, conductivity, and mechanical properties.

Properties of PEDOT:PSS include relatively good environmental and thermal stability, high electrical conductivity for a polymer, and appreciable optical transparency in thin films. Conductivity can reach several thousand siemens per centimeter in optimized PEDOT:PSS formulations, though devices with lower content or without post-treatment exhibit lower values. Thin PEDOT:PSS layers can be optically transparent in the visible spectrum while acting as conductive films, making them attractive as transparent electrodes. The work function of PEDOT-based films is typically in the range of about 4.8 to 5.0 eV, useful in hole-transport and interface engineering.

Applications of PEDOT and PEDOT:PSS are wide-ranging. They include transparent conductive electrodes for organic electronics and solar cells, antistatic coatings, electrochromic devices, flexible and printed electronics, energy storage such as supercapacitors, and neural or bioelectronic interfaces. Ongoing research explores alternative dopants, processing methods, and composite formulations to further enhance conductivity, stability, and functionality.