Poly(9,9-di-n-octylfluorenyl-2,7-diyl), known as F8 or PFO, is a polyfluorene specifically optimized for a variety of organic electronic applications.

General Information

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CAS Number	19456-48-5
Chemical Formula	(C29H41)n
Full Name	Poly(9,9-di-n-octylfluorenyl-2,7-diyl)
Recommended solvents	Toluene, xylene, chlorobenzene
Synonyms	F8 PFO
Classification / Family	Polyfluorenes, Benzothiodiazoles, Organic semiconducting materials, Semiconducting polymers, OLED green emitter materials, OLED materials, Organic photovoltaic (OPV) materials, Polymer solar cells, OFET materials

Chemical Structure

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Chemical structure of PFO (F8). CAS No. 19456-48-5. Chemical formula: (C29H41)n.

Characterization

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F8 distribution plot

Applications

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For a high-efficiency green OLED we recommend blending F8 with F8BT with the below specifications. This ink can then be applied either in air, or in a glove box, with little difference in performance (provided exposure time and light levels are minimised). For more details see our fabrication guide.

At typical concentrations of 10 mg/ml, 100 mg of F8 (PFO) will make around 200 devices on Ossila's standard ITO substrates (20 x 15 mm), assuming 50% solution usage (50% loss in filtering and preparation).

OLED reference device:

• F8 with F8BT
• Blend ratio of 19:1 (F8:F8BT) in Toluene
• Total concentration of 10 mg/ml
• 0.45 μm PTFE filter (hydrophobic)
• Spun at 2000 rpm (approx. 70 nm thickness)

Pipetting 20 μl of the above solutions onto a substrate spinning at 2000 rpm should provide a good even coverage, with approximately 70 nm thickness. The substrate needs to be spun until dry, which is typically only a few seconds — 15 seconds should be ample to achieve this. Thermal annealing should be undertaken at 80°C for 10 minutes prior to cathode deposition.

Typical Device Architectures and Performance

A basic, efficient OLED can be made using PEDOT:PSS as a hole-transport layer and Calcium/Aluminum as the electron contact. When used with the Ossila ITO glass OLED substrates and shadow masks this produces an easy to fabricate yet efficient >100 cd/m2 device.

Typical Ossila device architecture: Polyfluorene-based OLED architecture based on F8 blended with F8BT.