TCNQ

Order Code: M681
MSDS sheet

Price

(excluding Taxes)

£59.00


Pricing

 Grade Order Code Quantity Price
Sublimed (>99.3% purity) M681 1 g £59
Unsublimed (>98% purity) M682 5 g £65
Sublimed (>99.3% purity) M681 5 g £265

General Information

CAS number 1518-16-7
Chemical formula C12H4N4
Molecular weight 204.19 g/mol
HOMO/LUMO LUMO = 4.5 eV
Synonyms

7,7,8,8-Tetracyanoquinodimethane

(2,5-Cyclohexadiene-1,4-diylidene)-dimalononitrile

2,2'-(2,5-Cyclohexadiene-1,4-diylidene)bismalononitrile

Classification / Family

Electron acceptor, Hole-injection materials, Hole transport layer material, Light-emitting diodes, Polymer solar cells, OFETs.

 

Product Details

Purity

Sublimed* >99.3%

Unsublimed >98%
Melting point 289 °C (dec.)
Colour Dark yellow to brown crystals/powder

*Sublimation is a technique used to obtain ultra pure grade chemicals to get rid of mainly trace metals and inorganic impurities. Sublimation happens under certain pressure for chemicals to only go through two physical stages from a solid sate to vapour (gas) and then the vapour condensed to a solid state on a cool surface (referred to as cold finger). The most typical examples of sublimation are iodine and dry ice. For more details about sublimation, please refer to sublimed materials for OLEDs and perovskites and our collection of sublimed materials.

 

Chemical Structure 

chemical structure of TCNQ
Chemical structure of 7,7,8,8-tetracyanoquinodimethane (TCNQ); CAS number 1518-16-7; Chemical formula C12H4N4.

 

Applications

7,7,8,8-tetracyanoquinodimethane (TCNQ), with a LUMO at 4.5 eV, is known for the charge transfer salts formed by its radical anion TCNQ, in photovoltaics and light-emitting diodes and organic field-effect transistor devices. TCNQ and its derivatives have been used as dopants, leading to an increase in the hole mobility or to the lowering of injection barriers. Classic example of such is the treatment of tetrathiafulvene (TTF), an electron donor with TCNQ. TFF and TCNQ form an ion pair, the TTF-TCNQ complex. This process of doping leads to the crystallisation of the ion pair into a one-dimensionally stacked polymer, consisting of segregated stacks of cations and anions of the donors and the acceptors, respectively. The complex crystal is an organic semiconductor that exhibits metallic electric conductivity [1, 2].

It also has been shown that TCNQ can effectively modify Cu or Ag surfaces. The formation of Cu-TCNQ and Ag-TCNQ enhances the work function of such electrodes and reduces the hole injection barrier dramatically. Furthermore, it improves electrodes/organic layer contact hence the reduction of contact resistances [3].

Tetracyanoquinodimethane (TCNQ) is also found to act as a p-type doping agent of graphene films due to its powerful electron accepting capacity [4].

 

Device structure ITO/0.4 wt% F4TCNQ doped α NPD (30 nm)/ 5 wt% Ir (ppy)3 doped CBP (50 nm)/BPhen (30 nm)/20 wt% TCNQ mixed BPhen (1.5 nm)/Al [5]
Colour Green   green
Luminance@15 V 1,320 cd/m2 
Power Efficiency@14 V 56.6 lm W1  
Current Efficiency@14 V 23.17 cd/A
Device structure                                       ITO/F4TCNQ (3 nm)/MeO-Spiro-TPD (27 nm)/CBP + BCzVbi* (50 nm)/BPhen (10 nm)/TCNQ mixed BPhen (1.5 nm)/Al [6]
Colour                                  Red   red
Luminance@ 10 mA/cm2 1,790 cd/m2
Power Efficiency@ 10 mA/cm2      4.65 lm W1  
Current Efficiency@ 10 mA/cm2 18.0 cd/A

*For chemical structure informations please refer to the cited references.

 

Characterisation

hplc trace of tcnq

HPLC trace of 7,7,8,8-tetracyanoquinodimethane (TCNQ).

 

Literature and Reviews

  1. The Difference between Metallic and Insulating Salts of Tetracyanoquinodimethane (TCNQ): How to Design an Organic Metal, J. B. Torrance, Acc. Chem. Res., 12 (3), 79-86 (1979).
  2. Organic electronics: When TTF met TCNQ, J. R. Kirtley et al., Nat. Mater.,  7, 520-521 (2008). doi:10.1038/nmat2211.
  3. Interface Engineering: An Effective Approach toward High-Performance Organic Field-Effect
    Transistors, C-A. Di et al., Acc. Chem. Res., 42 (10), 1573-1581 (2009).
  4. Layer-by-Layer Graphene/TCNQ Stacked Films as Conducting Anodes for Organic Solar Cells,
    C-L. Hsu et al., ACS. Nano., 6 (6), 5031-5039 (2012). DIO: 10.1021/nn301721q.
  5. Novel organic electron injection layer for efficient and stable organic light emitting diodes, R. Grover et al., J. Luminescence, 146, 53–56 (2014). http://dx.doi.org/10.1016/j.jlumin.2013.09.004.
  6. Light outcoupling efficiency enhancement in organic light emitting diodes using an organic scattering layer, R. Grover et al., Phys. Status Solidi RRL 8 (1), 81–85 (2014). DOI: 10.1002/pssr.201308133.
  7. Photoconductive response in organic charge transfer interfaces with high quantum efficiency, H. Alves et al., Nat. Commu., 4:1842 (2012). DOI: 10.1038/ncomms2890.
  8. Formation of an intermolecular charge-transfer compound in UHV codeposited tetramethoxypyrene and tetracyanoquinodimethane, K. Medjanik et al., Phys. Rev., 82, 245419 (2010).