TIPS-Pentacene

Order Code: M151
MSDS sheet

Price

(excluding Taxes)

£98.00


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 selected other geographical areas outside of North America. TIPS pentacene has become widespread 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. This Ossila 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.

 

Datasheet

 

 TIPS Pentacene structure

Specifications

Full name 6,13-Bis(triisopropylsilylethynyl)pentacene
Synonyms TIPS-pentacene
CAS number 373596-08-8
Molecular formula C44H54Si2
Molecular weight 639.07 g/mol
Appearance Dark blue solid
Solvents Anisole, butylbenzene, chlorobenzene, chloroform, dichlorobenzene, tetrahydrofuran, toluene, xylene
Recommended solvent Toluene
Recommended concentration 10 mg/ml (drop cast / spin cast)

 

HPLC trace for TIPS pentacene
HPLC data

 

1H-NMR trace for TIPS pentacene
NMR trace

 

Usage Details

Condensed Fabrication Routine

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.

Ossila pre-patterned Si/SiO2 substrates (low density) with gold source-drain contacts
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

 

Results

The image below depicts the best performance OFET, showing 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.

 

TIPS pentacene OFET crystals TIPS pentacene crystals across OFET channel
Aligned TIPS crystalline domains

 

The table below summarises the mobility and threshold voltage for the three PTES-treated substrates.

 

Substrates Data Device 1 Device 2 Device 3 Device 4 Device 5
1 μ (cm2/Vs) - 0.928 - - 0.145
1 Vt (V) - -3.53 - - +2.25
2 μ (cm2/Vs) 0.174 0.148 0.307 0.105 0.28
2 Vt (V) +0.27 -4.67 -3.21 -6.78 -0.76
3 μ (cm2/Vs) 0.377 0.322 0.269 0.252 -
3 Vt (V) -12.99 -9.45 -10.42 -7.57 -

 

TIPS pentacene output characteristics TIPS pentacene transfer characteristics
Left Side: Output currents of the best performing top-contact OFET for six different gate voltages.
Right side: Same device transfer characteristic in saturation mode (Vds = -40 V).

 

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 vapour saturated condition inside the Petri dish.

 

Condensed Device Fabrication Routine

TIPs Pentacene Solution Preparation

Preparation 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 results in molecular degradation and increased water content of the solution.

 

Top Contact OFET

Substrate cleaning

  • 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-dry 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 with a probe station under air and light using the Ossila FACT1 software and National Instruments 4132 PXI.

To download the full report click here

 

Crystallisation Images

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 especially in slow dried films.

 

TIPS pentacene small crystals from 1000 rpm spin cast film
TIPS pentacene Spin coated 1000 rpm

 

TIPS pentacene medium crystals from 300 rpm spin cast film
TIPS pentacene Spin coated 300 rpm

 

TIPS pentacene large crystals from drop cast film
TIPS pentacene Drop cast (covered)

 

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.