PEDOT:PSS

Order Code: M121

Price

(excluding Taxes)

£149.00


PEDOT:PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) is a transparent conductive polymer consisting of a mixture of two ionomers. Due to its unique combination of conductivity, transparency, ductility, and ease of processing, PEDOT:PSS has become a benchmark material in thin-film electronic fabrication. PEDOT:PSS can be used as an interfacial layer for hole transport in organic light emitting diodes, organic photovoltaics, and perovskite photovoltaics. It can also be used as a replacement for transparent conductors such as ITO or FTO and is used commonly in applications where the underlying substrate is flexible.

Ossila supplies a range of PEDOT:PSS and PEDOT dispersions that are suitable for different applications these include:

PEDOT dispersion Primary use
Al 4083 Interfacial layers in photovoltaic (OPV) and light emitting diodes (OLED)
PH 1000 High conductivity films and interfacial layers
HTL Solar Surfaces that are difficult to wet with an aqueous dispersion
HTL Solar 3 A toluene dispersion for when a water-based dispersion is an issue (e.g. glovebox)

For guides on surface preparation and deposition of thin films see our processing guide section at the bottom of this page, and for more information of the application of PEDOT:PSS see our applications section or for a list of frequently asked question see our FAQ section at the bottom of the page.

 

PEDOT:PSS (Al 4083)

Heraeus Clevios™ AI 4083 is one of the most commonly used PEDOT:PSS formulations, due to its deep work function it is often used for matching of interfacial energy levels in thin film electronic devices. 

 

Al 4083 specifications and MSDS

Resistivity 500-5000 Ω.cm
Solid content 1.3 to 1.7 wt.% (in water)
Viscosity 5-12 mPa.s
PEDOT:PSS ratio 1:6
Particle Size Distribution D90 = 100nm; D50 = 80nm
Work function 5.0 - 5.2 eV
CAS number 155090-83-8
Packaging 100 ml of solution sealed in a light resistant bottle with temperature indicator

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PEDOT:PSS (PH 1000)

Heraeus Clevios™ PH1000 PEDOT:PSS is designed for applications where high conductivity and optical transparency are required. The potential uses for high conductivity PEDOT:PSS formulations include replacements for ITO, semitransparent top electrodes in thin film electronics, top gate electrodes in FETs, and for use as a thick planarisation layer on rough surfaces such as FTO. Sheet resistances as low as 300 Ω/square can be achieved with the addition of conductivity enhancement agents such as dimethylsulfoxide and ethylene glycol.

 

PH 1000 specifications and MSDS

Resistivity <0.0012 Ω.cm
Solid content 1.0 - 1.3 wt.% (in water)
Viscosity < 50 mPa.s
PEDOT:PSS ratio 1:2.5
Particle Size Distribution D50 = 30nm
Work Function 4.8 - 5.0 eV
CAS number
155090-83-8
Packaging 100 ml of solution sealed in a light resistant bottle with temperature indicator

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PEDOT:PSS (HTL Solar)

Heraeus Clevios™ HTL Solar is a PEDOT:PSS formulation designed for use in thin film electronics as an interfacial material. The advantage of the HTL Solar formulation is its improved wetting properties, particularly in inverted OPV cells, compared to the other PEDOT:PSS formulations in our catalogue.

 

HTL Solar specifications and MSDS

Resistivity 1 - 10 Ω.cm
Solid content 1.0 - 1.2 wt.% (in water)
Viscosity 8 to 30 mPa.s
PEDOT:PSS ratio 1:2.5
Work Function 4.8 - 5.0 eV
CAS number
155090-83-8
Packaging 100 ml of solution sealed in a light resistant bottle with temperature indicator

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PEDOT:complex (HTL Solar 3)

Heraeus Clevios™ HTL Solar 3 is a PEDOT formulation using a alternative counter ionomer to PSS to allow for the dispersion in toluene. HTL Solar 3 is ideal for use with materials or in environments that are water sensitive, such as in glove box environments or for use with perovskite materials.

 

HTL Solar 3 specifications and MSDS

Resistivity 5-500 Ω.cm
Solid content 1.5 to 2.5 wt.% (in toluene <0.5% water)
Viscosity <10 mPa.s
PEDOT:PSS ratio N/A
Work function 4.4eV - 4.8eV
CAS number 155090-83-8
Packaging 2 x 25 ml of solution sealed in a light resistant bottles with temperature indicator

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PEDOT:PSS Applications

Perovskite photovoltaics: PEDOT:PSS has been used as a hole extraction material in inverted devices in order to facilitate the extraction of charge carriers at the interface between the transparent conductive oxide and the active perovskite layer. Inverted perovskite devices using PEDOT:PSS typically show lower hysteresis than standard architecture devices. In addition recent work on standard architecture devices show that the toluene based PEDOT:PSS can be used as a cheap alternative to spiro-OMeTAD.

  • Efficient organometal trihalide perovskite planar-heterojunction solar cells on flexible polymer substrates, H. J. Snaith et. al. Nature Communications, 4, (2013) DOI: 10.1038/ncomms3761
  • High efficiency stable inverted perovskite solar cells without current hysteresis, M. Grätzel et. al. Energy Environ. Sci. 8, (2015) 2725-2733 DOI: 10.1039/c5ee00645g
  • Employing PEDOT as the p-type charge collection layer in regular organic-inorganic perovskite solar cells, H. J. Snaith et. al. J. Phys. Chem. Lett. 6 (9), (2015) 1666-1673 DOI: 10.1021/acs.jpclett.5b00545 

 

Organic photovoltaics: PEDOT:PSS has long been used as a standard material in device fabrication, it has been extensively used with materials such as P3HT and PCDTBT to form the backbone of fundamental research into polymer solar cells. In addition PEDOT:PSS is still used in combination with the state of the art organic photovoltaic materials to push new efficiency limits.

  • Nanoscale morphology of high-performance polymer solar cells, R. A. J. Janssen, Nano Lett. 5 (4), (2005) 579-583 DOI: 10.1021/nl048120i
  • Bulk heterojunction solar cells with internal quantum efficiency approaching 100%, A. J. Heeger et.al. Nature Photonics, 3, (2009) 297-302 DOI: 10.1038/nphoton.2009.69
  • Single-junction organic solar cells based on a novel wide-bandgap polymer with efficiency of 9.7%, Y. Sun et. al. Adv. Mater. 27 (18), (2015) 2938-2944 DOI: 10.1002/adma.201500647

 

Organic light emitting diodes: The use of PEDOT:PSS in organic light emitting diodes has been widespread for over a decade now and is a well established standard hole injection material. More recent work still uses PEDOT:PSS due to its deep work function allowing for efficient charge injection into white emitting polymers and also host materials for thermaly activated delayed fluorescence materials.

  • Molecular organic light-emitting diodes using highly conducting polymers as anodes, H. Kafafi et. al. Appl. Phys. Lett. 80, (2002) 3844 DOI: 10.1063/1.1480100
  • High-efficiency white-light-emitting devices from a single polymer by mixing singlet and triplet emissionY. Cao et. al. Adv. Mater. 18, (2006) 1769-1773 DOI: 10.1002/adma.200502740
  • A universal host material for high external quantum efficiency close to 25% and long lifetime in green fluorescent and phosphorescent OLEDs, J. Y. Lee et. al. Adv. Mater. 26, (2014) 4050-4055 DOI: 10.1002/adma.201400347

 

Transparent conductor: PEDOT:PSS has been seen as a potential replacement for expensive transparent metal oxides such as ITO and FTO and has been shown in both organic photovoltaic and perovskite photovoltaic devices to be an effective replacement. In addition, in combination with metallic grid structures sheet resistances comparable to metallic films are possible.

  • Highly conductive PEDOT:PSS electrode by simple film treatment with methanol for ITO-free polymer solar cells, C. W. Chu et. al. Energy Environ. Sci. 5, (2012) 9662-9671 DOI: 10.1039/C2EE22595F
  • Flexible high power-per-weight perovskite solar cells with chromium oxide-metal contacts for improved stability in air, S. Bauer et. al. Nature Materials, 14, (2015) 1032-1039 DOI: 10.1038/nmat4388
  • All solution roll-to-roll processed polymer solar cells free from indium-tin-oxide and vacuum coating steps, F. C. Krebs, Org. Electron. 10 (5), (2009) 761-768 DOI: 10.1016/j.orgel.2009.03.009

     

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    PEDOT:PSS Processing Guides

    Surface Preparation

    For preparation of the surface of a substrate for deposition of PEDOT:PSS you will need the following products: FTO Glass/ITO Glass/Glass/SiO2 substrate, 1.1mm Substrate Rack/2.2mm Substrate Rack (product coming soon), Hellmanex iii, isopropyl alcohol, and UV Ozone Cleaner. The following is a step-by-step guide for preparing surfaces for the deposition of PEDOT:PSS, an instructional video is provided below.

    • Sonicate chosen substrate for 5 minutes in hot (70°C) DI water with the addition of 1% Hellmanex.

    • Dump-rinse twice in boiling DI water.

    • Sonicate chosen substrate for 5 minutes in Isopropyl alcohol.

    • Dump-rinse twice in boiling DI water.

    • Dry chosen substrate using filtered compressed gas.

    • Place the chosen substrate into the UV Ozone cleaner and leave for 10 minutes.  

     

     

    Deposition of PEDOT:PSS
    For the deposition of thin films of PEDOT:PSS on a freshly prepared surface you will need the following products: FTO Glass/ITO Glass/Glass/SiO2 Substrate, Amber Vial, 0.45μm PVDF/PTFE Filter, Solvent Safe Syringe, PEDOT:PSS, Micropipette, Spin Coater, and Hot Plate.
    • Filter your PEDOT:PSS solution through the 0.45um PVDF filter into an amber vial (if using HTL Solar 3 use a PTFE filter).
    • Preheat the hot plate to 120°C
    • Place a freshly prepared substrate into the spin coater and set to the desired spin speed.
    • For speeds below 1000 rpm we recommend static spin coating or the solution for higher speeds dynamic spin coating can be done.
    • The substrates should be spun until the films are dry, for PEDOT:PSS films this is typically >30s.
    • Once the spin coating has finished place the samples on the hotplate for 15 minutes to fully dry.

     

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    Frequently Asked Questions

    PEDOT:PSS is a polymeric material containing a mixture of two different ionomers, these being poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate. PEDOT:PSS typically comes as a water based emulsion which is created via the polymerization of EDOT monomers in a polystyrene sulfonic acid solution. Due to its unique combination of conductivity, transparency, ductility, and ease of processing, PEDOT:PSS has become a benchmark material in thin-film electronic fabrication. PEDOT:PSS can be used as an interfacial layer for hole transport in thin film electronics. It can also be used as a replacement for transparent conductors such as ITO or FTO and is used commonly in applications where the underlying substrate is flexible.

    The electrical conductivity of oxidized polythiophenes has been known about for nearly 40 years, the origins of this conductivity are due to the presence of radical states which are formed due to the oxidation of the thiophene units. These reduced states are delocalized across the polymer chain, in the presence of the oxidizer these radicalized states can be stabilized. In PEDOT:PSS the EDOT is oxidized during the polymerisation reaction by the polystyrene sulfonate, this produces an emulsion where the PSS present stabilizes the radical states on the PEDOT.

    Although PEDOT itself is conductive the PSS present within the blend is insulating therefore the quantity of PSS and the microsctructure of the film have a significant impact on the electronic properties of PEDOT:PSS. In a water based dispersion the PEDOT and PSS form a micelle structure in which the hydrophobic PEDOT core is surrounded by a shell of hydrophilic PSS. During deposition this structure is retained forming localized regions of conductive PEDOT surrounded by insulating regions of PSS. It is this core-shell structure which results in the low conductivity values that can arise for standard formulations of PEDOT:PSS.

    Advanced formulations offer increased conductivity of PEDOT:PSS thin films, this is achieve by the addition of secondary solvents (sometimes referred to as secondary dopants) to the solution or exposing thin films to these secondary solvents. Originally it was believed these solvents acted by further doping the PEDOT (hence the name secondary dopant), however more recent work has revealed that the presence of these solvents work to change the core-shell structure which is seen normally.

    When exposed to these solvents the hydrophilic/hydrophobic nature of the PSS/PEDOT components no longer determine the structure. The solvents allow the diffusion and intermixing of the PEDOT and PSS chains creating a more homogenous film on the microscale. This homogenisation increases the path length of charges along the PEDOT chain reducing the distance that charges must travel across PSS rich areas.

    As work function is a surface property of a material the work function of the PEDOT:PSS blend will be determined by the percentage of each component at the surface of the film. PSS has a significantly deeper work function than PEDOT, therefore a higher presence of PSS at the surface will result in a deeper work function. This means that for formulations with higher percentages of PSS the work function will be higher than those with lower percentages. In addition the processing of the PEDOT:PSS film can result in changes to the work function. As mentioned in the ‘how do I improve the conductivity of PEDOT:PSS’ section the PEDOT:PSS forms a core-shell structure resulting in PEDOT being surrounded by PSS. In this case the work function will be dominated by PSS, however if the film has been treated such that the components are more homogenously dispersed the work function will become more shallow as the surface becomes richer with PEDOT..

    The coating quality of the PEDOT:PSS will be dependent upon several factors, these include the PEDOT formulation you are using, the deposition technique, the surface you are depositing onto, and the cleanliness of the surface. Ideally the film should be highly uniform across the entire surface with possible variations at the ends of your sample due to edge effects. Sometimes due to the wetting conditions of the PEDOT formulation on the surface the coating may not be uniform, if this occurs there are several things that can be done. The first is to ensure that the surface of your sample is clean, if possible use a combination of solvent cleaning steps and UV ozone or oxygen plasma treatments to ensure a completely clean surface (for more information on surface preparation see our guide above). If this does not improve the quality of the surface the addition of secondary solvents can be done, for AI 4083 and PH1000 the addition of approximately 10% isopropanol can improve the wetting on surfaces.

     

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    To the best of our knowledge the technical information provided here is accurate. However, Ossila assume no liability for the accuracy of this information. The values provided here are typical at the time of manufacture and may vary over time and from batch to batch.