6,13-bis(triisopropylsilylethinyl)pentacene commonly known as TIPS pentacene.
A high-purity TIPS-Pentacene for use in organic field-effect transistors (OFETs). In stock for immediate delivery to academic institutions in Europe and other selected geographical areas outside of North America. TIPS-Pentacene is widely used as a high performance small molecule for OFET applications, with a mobility in excess of 1 cm2/Vs having being achieved in the literature. It has excellent solubility in a range of common organic solvents, and a good ambient stability - making it easy to process into devices. Ossila's TIPS-pentacene has been produced with a purity of >99.9%.
Please note that TIPS-Pentacene is unavailable to buyers in the USA. Any incoming orders from the USA for TIPS-Pentacene will not be processed.
|Molecular weight||639.07 g/mol|
|Appearance||Dark blue solid|
|Solvents||Anisole, butylbenzene, chlorobenzene, chloroform, dichlorobenzene, tetrahydrofuran, toluene, xylene|
|Recommended concentration||10 mg/ml (drop cast / spin cast)|
OFET fabrication procedure
We have achieved a mobility of approximately 0.92 cm2/Vs using TIPS-Pentacene for top contact OFETs with a drop casting protocol. The TIPS-Pentacene film is obtained through slow crystallisation growth at high temperature (50°C), in solvent saturated ambient, over silicon oxide substrates treated with phenyl-terminated silane molecules.
The image below depicts the best performance OFET, showing how the boundaries of the crystals forming the crystallite domain have boundaries parallel to the channel length. Cracks perpendicular to the growth direction are also clearly visible. These cracks act as defects (bottlenecks for charge transport) and must be minimised in order to obtain high-performing OFETs.
The table below summarises the mobility and threshold voltage for the three PTES-treated substrates, taking an average of 75% of the 15 OFET devices to minimise the maximum and minimum outliers.
|Devices Measured||Mobility (cm2/Vs)||VT (V)|
|15||0.28 +/- 0.06||-5.14 +/- 2.75|
Drop casting details
The direction of the crystal growth, and therefore the orientation of the crystal axes (with respect to the channel length), can be controlled by imposing a preferential drying direction to the drop casted solution. This is achieved by positioning the substrate inside a Petri dish at a 3.5° angle with respect to the horizontal line of a perfectly flat hot plate. Substrates are placed inside the Petri dish in a manner such that the length of the channel is perpendicular to the receding direction of the drying solution. Drop casting is carried out using a pipette with the substrate at a temperature of 50°C. The lid was put back immediately afterwards to trap the solvent vapour and create a vapour-saturated condition inside the Petri dish.
Images below taken of thin films of TIPS-pentacene deposited by spin casting and drop casting from toluene (10 mg/ml) on SiO2, showing the strong crystallisation behaviour in slow dried films.
OFET device specifications
This table shows details of the substrates used in this fabrication routine.
|Substrates||Ossila silicon/silicon dioxide substrates (S146)|
|Substrate size||20 x 15 mm|
|Gate conductivity||1-30 Ω·cm (Boron doped)|
|Silicon oxide thickness||300 nm|
|Device per substrates||five, common gate|
|Channel length||30 µm|
|Channel width||1000 µm|
|OFET architecture||Top contact, bottom gate|
|Source-Drain patterning||Thermal evaporation using Source-Drain Deposition Mask for Low Density OFETs|
TIPS-Pentacene Solution PreparationPreparation of the solution took place in a glove box (O2 << 10 ppm; H2O)
- TIPS-Pentacene dissolved in anhydrous Toluene, 10 mg/ml
- Vial is placed on a hotplate at 60°C for 1 hour at 1000 rpm with a magnetic stirrer
- Solution was then filtered with 0.45 µm filter into a new vial
- Prior to decanting the stock solution was placed on a hotplate at 60°C for 1 hour
- Required amount was diluted with anhydrous Toluene 2 mg/ml
The solution used for drop-casting was prepared only when needed. TIPS-Pentacene is relatively resilient to oxidation at room temperature. However, long permanence in normal ambient condition (>24 hrs) can result in molecular degradation and increased water content of the solution.
- 1% Hellmanex III solution in hot DI water
- Sonicate for 5 min in hot water
- Rinse twice in hot water
- IPA, Sonicate 5 min in hot water
- Rinse twice in DI water (cold)
- Store substrates in DI water
- Oxygen plasma treatment for 4 min at P = 100 W
- PTES treatment Trichloro(phenethyl)silane, 3 mMol in Toluene, for 15 hrs in glove box at 90°C or, alternatively
- PTS treatment, Trichloro(phenyl)silane, 3% in weight in glove box at 90°C for 15 hrs
- Substrates rinsed twice in glove box with Toluene, then blow-dried and brought outside a glove box
- Sonicated in 1 ml of Toluene for 10 minutes
- Blow dry, rinsed with 2 ml in running acetone, blow dry, rinsed with 2 ml of running IPA, blow dry
- Put in glove box on hotplate at 150°C for 5 min
TIPS-Pentacene drop casting
- Pipette 50 μl of TIPS solution (2 mg/ml) onto the substrate
- Cover with glass lid for 5 minutes on a hot plate at 50°C
- Switch off the hot plate, swap the glass lid with filter paper, left one minute to cool down
- Remove the Petri dish from the hot plate, left the substrate in Petri dish to cool down for extra three minutes
- Wipe clean the substrates with the exception of the area over which the drain and source are to be deposited
- Load the evaporation stack
Deposition of top contact gold
- Load Edwards evaporator
- Leave the substrates for 15 hrs in vacuum (2.3 x 10-6 mBar)
- Deposition of about 100 nm of gold on TIPS-Pentacene
- Cooling for 1 hour under vacuum
OFETs were measured using an Ossila Test Board for Low-Density OFETs (E222) under air.
To download the full report click here
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.