WO2009016107A1 - Method for depositing a semiconducting layer from a liquid - Google Patents

Method for depositing a semiconducting layer from a liquid Download PDF

Info

Publication number
WO2009016107A1
WO2009016107A1 PCT/EP2008/059767 EP2008059767W WO2009016107A1 WO 2009016107 A1 WO2009016107 A1 WO 2009016107A1 EP 2008059767 W EP2008059767 W EP 2008059767W WO 2009016107 A1 WO2009016107 A1 WO 2009016107A1
Authority
WO
WIPO (PCT)
Prior art keywords
compounds
semiconducting
substrate
mixture
polymeric
Prior art date
Application number
PCT/EP2008/059767
Other languages
French (fr)
Inventor
Subramanian Vaidyanathan
Marcel Kastler
Florian DÖTZ
Original Assignee
Basf Se
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Basf Se filed Critical Basf Se
Publication of WO2009016107A1 publication Critical patent/WO2009016107A1/en

Links

Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/10—Deposition of organic active material
    • H10K71/12—Deposition of organic active material using liquid deposition, e.g. spin coating
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K10/00—Organic devices specially adapted for rectifying, amplifying, oscillating or switching; Organic capacitors or resistors having potential barriers
    • H10K10/40—Organic transistors
    • H10K10/46—Field-effect transistors, e.g. organic thin-film transistors [OTFT]
    • H10K10/462—Insulated gate field-effect transistors [IGFETs]
    • H10K10/464—Lateral top-gate IGFETs comprising only a single gate
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/60—Organic compounds having low molecular weight
    • H10K85/649—Aromatic compounds comprising a hetero atom
    • H10K85/655—Aromatic compounds comprising a hetero atom comprising only sulfur as heteroatom

Definitions

  • the present invention relates to a process for depositing a semiconducting layer comprising one or more semiconductor compounds and one or more polymeric compounds in a solvent on a substrate.
  • An object of the present invention is therefore a method for depositing a semiconducting layer comprising a low molecular weight semiconducting compound a high molecu- lar weight insulating polymer compound of better mobility and decreased fluctuations and wastage.
  • a method comprising the steps:
  • a substrate comprising a surface on which a semiconducting layer is to be deposited.
  • the substrate may be made of any material and may be of any shape if its function to support the semiconducting layer and other layers is not hindered.
  • the substrate has the form of films or sheets which may be easily manufactured by extrusion processes if polymers are used.
  • the substrate may be formed from organic materials like organic polymers or inorganic materials like Si or metals.
  • the substrate comprises a polymer selected from the group consisting of polyethylene therephthalate (PET), polyethylene naphthalate (PEN), polyimine (Pl), and the like without being restricted thereto.
  • PET polyethylene therephthalate
  • PEN polyethylene naphthalate
  • Pl polyimine
  • the substrate is an organic polymer film.
  • the surface comprises at least one source and drain electrode or at least one gate electrode.
  • step b) of the present invention a mixture comprising one or more semiconducting compounds and one or more polymeric compounds in a liquid is provided.
  • the semiconducting compound(s) are monomeric or oli- gomeric.
  • monomeric or oligomeric means that there are only one or up to about 20 repeating units in the molecule in (weight) average.
  • the semiconducting compound comprises 1 to 5 repeating units, most preferably the semiconducting compound is monomeric, dimeric or trimeric.
  • Repeating units according to the present invention mean the part of the molecule repeating in identical form. Normally the repeating units correspond to the respective monomers.
  • the semiconducting compound may be a single compound or a mixture of compatible semiconducting compounds.
  • Semiconducting compounds useful for the present invention are generally known in the art.
  • the organic semiconducting compound may be an n or p type.
  • Preferred semiconducting layers have a FET mobility of greater than 10 "5 Cm 2 V- 1 S "1 , more preferably greater than 10 "4 Cm 2 V- 1 S “1 , most preferably greater than 10 "3 Cm 2 V- 1 S "1 .
  • the organic semiconductor may be any conjugated aromatic molecule containing at least three aromatic rings.
  • Preferred organic semiconductors contain 5, 6 or 7 mem- bered aromatic rings, especially preferred organic semiconductors contain 5 or 6 mem- bered aromatic rings.
  • Each of the aromatic rings may optionally contain one or more hetero atoms selected from Se, Te, P, Si, B, As, N, O or S, preferably from N, O or S.
  • the rings may be optionally substituted with alkyl, alkoxy, polyalkoxy, thioalkyl, acyl, aryl or substituted aryl groups, a fluorine atom, a cyano group, a nitro group or an optionally substituted secondary or tertiary alkylamine or arylamine -N(R 3 )(R 4 ), where R 3 and R 4 each independently is H, optionally substituted alkyl, optionally substituted aryl, alkoxy or polyalkoxy groups.
  • the alkyl and aryl groups may be optionally fluorinated.
  • T 1 and T 2 each inde- pendently represent H, Cl, F, -C ⁇ N or lower alkyl groups particularly Ci -4 alkyl groups ;
  • R' represents H, optionally substituted alkyl or optionally substituted aryl.
  • the alkyl and aryl groups may be optionally fluorinated.
  • organic semiconducting compounds that can be used in this invention include compounds, oligomers and derivatives of compounds of the following list: Conjugated hydrocarbon polymers such as polyacene, polyphenylene, poly (phenylene vinylene), polyfluorene including oligomers of those conjugated hydrocarbon polymers ; condensed aromatic hydrocarbons such as anthracene, tetracene, chrysene, penta- cene, pyrene, perylene, coronen ; oligomeric para substituted phenylenes such as p- quaterphenyl (p-4P), p-quinquephenyl (p-5P), p-sexiphenyl (p-6P) ; conjugated heterocyclic polymers such as poly (3-substituted thiophene), poly (3, 4-bisubstituted thio- phene), polybenzothiophene, polyisothianapthene, poly(N-substit
  • a preferred class of semiconductors has repeat units of formula 1 :
  • each Y 1 is independently selected from P, S, As, N and Se and preferably pol- yarylamines, where Y 1 is N ; Ar 1 and Ar 2 are aromatic groups and Ar 3 is present only if Y 1 is N, P, or As in which case it too is an aromatic group.
  • Ar 1 , Ar 2 and Ar 3 may be the same or different and represent, independently if in different repeat units, a multivalent (preferably bivalent) aromatic group (preferably mononuclear but optionally polynu- clear) optionally substituted by at least one optionally substituted C1-40 carbyl-derived groups and/or at least one other optional substituent, and Ar 3 represents, independently if in different repeat units, a mono or multivalent (preferably bivalent) aromatic group (preferably mononuclear but optionally polynuclear) optionally substituted by at least one : optionally substituted C1-40 carbyl-derived group and/or at least one other optional substituent ; where at least one terminal group is attached in the polymer to the Ar 1 , Ar 2 and optionally Ar 3 groups located at the end of the polymer chains, so as to cap the polymer chains and prevent further polymer growth, and at least one terminal group is derived from at least one end capping reagent used in the polymerisation to form said polymeric material to control the molecular weight thereof.
  • the number average degree of polymerisation is denoted by n and the number of the repeat units of Formula 1 which may be present per molecule in the invention may be from 2 to 1 , 000, preferably 3 to 100 and more preferably 3 to 20 inclusive.
  • the polymer may comprise a mixture of different polymeric species of varying chain lengths and with a distribution of molecular weights (polydisperse) or consist of molecules of a sin- gle molecular weight (monodisperse).
  • the preferred polymeric materials are obtainable by polymerisation controlled by the addition of at least one end capping reagent in an amount sufficient to reduce substantial further growth of the polymer chain.
  • Polymers may be further substituted with, on average, more than one aryl moiety which is further substituted with a moiety capable of chain extension or cross linking, for example by photopolymerisation or by thermal polymerisation.
  • moities capable of chain extension are preferably hydroxy, glycidyl ether, acrylate ester, epoxide, methac- rylate ester, ethenyl, ethynyl, vinylbenzyloxy, maleimide, nadimide, trifluorovinyl ether, a cyclobutene bound to adjacent carbons on an aryl moiety or a trialkylsiloxy.
  • amine materials that may be useful in this invention are tetrakis (N, N-aryl) biary- idiamines, bis (N, N'-[substituted]phenyl) bis (N, N'-phenyl)-1 , 1- biphenyl-4, 4-diamines including 4-methyl, 2, 4-dimethyl and/or 3-methyl derivatives thereof, tetrakis (N, N- aryl) biphenyl-4, 4'-diamine-1 , 1-cyclohexanes and their derivatives, triphenylamine and its alkyl and aryl derivatives and poly (N-phenyl-1 , 4-phenyleneamine), N-dibenzo
  • Conjugated oligomeric and polymeric heterocyclic semiconductors may comprise a repeat unit of an optionally substituted 5 membered ring and terminal groups A1 and A2 as shown in Formula 2:
  • X may be Se, Te or preferably O, S, or -N(R)- where R represents H, option- ally substituted alkyl or optionally substituted aryl ;
  • R 1 , R 2 , A 1 and A 2 may be independently H, alkyl, alkoxy, thioalkyl, acyl, aryl or substituted aryl, a fluorine atom, a cyano group, a nitro group or an optionally substituted secondary or tertiary alkylamine or arylamine -N(R 3 ) (R 4 ), where R 3 and R 4 are as defined above.
  • the alkyl and aryl groups represented by R 1 , R 2 , R 3 , R 4 , A 1 and A 2 may be optionally fluorinated.
  • the number of recurring units in the conjugated oligomer of Formula 2 is represented by an integer n, n is defined as for Formula 1. In compounds of Formula 2 n is preferably 2 to 14.
  • Oligomers containing a conjugated linking group may be represented by Formula 3:
  • the semiconducting channel may also be a composite of two or more of the same ty- pes of semiconductors.
  • a p type channel material may, for example be mixed with n-type materials for the effect of doping the layer.
  • Multilayer semiconductor layers may also be used.
  • the semiconductor may be intrinsic near the insulator interface and a highly doped region can additionally be coated next to the intrinsic layer.
  • the one or more semiconductor compounds have a molecular weight of 1000 g/mol or less, in particular 500 g/mol or less.
  • the one or more semiconductor compounds are monomeric or oligomeric organic compounds with up to ten monomeric units, particularly with up to five monomeric units.
  • the one or more semiconductor compounds are selected from the group consisting of substituted thiophenes, thiophene phenylene co- oligomers, polyacenes or polyheteroacenes, particularly pentacenes, or fluorenes, preferably in monomeric or oligomeric form.
  • the mixture of the present invention comprises one or more polymeric compounds.
  • the polymeric compound(s) may be a single compound or a mixture of compounds and may be made of insulating and/or semiconducting compound(s).
  • the one or more polymeric compound(s) are insulators.
  • all insulating polymers like isotactic or atactic polystyrene, polyethylene, particularly polyethylene having a density of 0,93 g/cm 3 or more, polypropylene can be used.
  • the mixture may contain further organic or inorganic compounds, however, it is preferred that the solution essentially consists of the one or more semiconducting compounds and the one ore more polymeric compounds. It is particularly preferred to have a mixture essentially consisting of a single semiconducting compound and a single polymeric compound.
  • the mixture may be provided in form of a homogene mixture, e. g. a solution, or a het- erogene mixture, e.g. an emulsion, suspension or dispersion.
  • a solution of the semiconducting and the polymeric compound is preferred.
  • the liquid may be a single compound or a mixture of compounds capable of solving or suspending the semiconducting compound and the polymeric compound under the process conditions.
  • Preferred liquids are toluene, THF and halogenated aromatics like dichlorobenzene, or mixture thereof, without being restricted thereto.
  • the viscosity of the liquid comprising the semiconducting compound can easily be adjusted by the ratio of the semiconducting compound to the polymeric compound in the solution and the amount of liquid used.
  • Preferred ratios of the semiconducting compound to the polymeric compound in the mixture are 99/1 (by weight) to 1/99, more preferably 90/10 to 10/90, most preferably 70/30 to 30/70.
  • preferred concentrations of the semiconducting compound in the liquid are less than 10 % by weight, more preferably 0.5 to 7.5 % by weight, most preferably 1 to 5 % by weight.
  • step c) at least part of the surface is brought into contact with the solution. Depending on the deposition method used the surface is brought into contact with the solution either completely or preferably only in the region of the moving zone.
  • step d) a zone of the mixture being in contact with the surface is moved along the surface in the moving direction.
  • the evaporation causes a concentration gradient along the moving direction. This concentration gradient must gen- erally be high enough, i.e. the evaporation must be fast enough to sufficiently remove the solvent from the solution to form a deposit of the semiconductor/polymer blend on the surface of the substrate.
  • the content of remaining solvent in the deposited semiconducting layer depends on the thickness of the deposited layer and on the properties of the polymer like molecular weight. Preferably the content is less than 20 %, more preferably less than 10%, most preferably less than 5 %.
  • the dimension (width) of the zone in moving direction is much shorter that the dimension (width) of the substrate to be coated with the semiconducting layer.
  • the perpendicular dimension (length) is preferably of the order of the dimension of the substrate (length).
  • the moving can be performed in two orientations, one where the source and drain electrodes are parallel to the moving direction of the foil, or where the source and drain structures are oriented perpendicular to said moving direction. Preferred is the perpendicular direction.
  • the velocity of moving is generally dependent on the removing rate of the solvent. Solvents having high boiling temperatures are generally less useful since the removal rate of the solvent at normal pressure will be too low. On the other hand, when using low boiling solvents the solvents evaporate to fast to allow any alignment of the polymer in the moving zone.
  • the boiling temperature (NTP) is from 50 -C to 210 -C, more preferably from 60 -C to 180 -C, most preferably from 65 -C to 1 10 -C.
  • Steps c) and d) may be performed at room temperature or at elevated temperature.
  • at least part, preferably the whole surface of the substrate is heated when depositing the semiconducting layer, e.g. from the backside of the substrate to speed up the evaporation of the solvent.
  • the moving zone itself may be heated, e.g. by radiation to cause or speed up evaporation of the solvent.
  • step d) is performed by drawing the substrate out of the solution.
  • the whole surface of the substrate is brought into contact with the liquid comprising the semiconducting compound and the polymeric compound and then slowly taken out of the liquid to ensure that at least part, preferably 50 %, more preferably 70 %, more preferably 80 %, more preferably 90 %, most preferably 95 % of the liquid are evaporated in the zone.
  • the zone width until the liquid content in the deposited semiconducting layer is below 5 % is below 10 mm, preferably about 1 mm to about 7 mm, most preferably about 1 mm to about 5 mm.
  • the zone width until the liquid content in the deposited layer is below 5 % in relation to the whole width of the substrate is generally about 0.5 % to about 20 %, preferably about 1 % to about 10 %, most preferably about 1 % to about 5 %.
  • the time for taking the substrate out of the liquid is depending on the liquid, particularly on the boiling point of the liquid.
  • the speed is preferably about 0.2 cm/h to about 10 cm/h, more preferably about 1 cm/h to about 4 cm/h, most preferably about 2 cm/h to about 3 cm/h.
  • step d) is performed by casting the solution over the substrate.
  • the area of the zone at one end of the substrate is brought into contact with the liquid comprising the semiconducting compound and the polymeric compound and then the zone is slowly moved across the substrate to the other end and thereby cast with the mixture.
  • At least part, preferably 50 %, more preferably 70 %, more preferably 80 %, more preferably 90 %, most preferably 95 % of the liquid are evaporated in the zone.
  • the zone width until the liquid content in the deposited semicon- ducting layer is below 5 % is below 10 mm, preferably about 1 mm to about 7 mm, most preferably about 1 mm to about 5 mm.
  • the zone width until the liquid content in the deposited layer is below 5 % in relation to the whole width of the substrate is generally about 0.5 % to about 20 %, preferably about 1 % to about 10 %, most preferably about 1 % to about 5 %.
  • the time for taking the substrate out of the liquid is depending on the liquid, particularly on the boiling point of the liquid.
  • the speed is preferably about 0.2 cm/h to about 10 cm/h, more preferably about 1 cm/h to about 4 cm/h, most preferably about 2 cm/h to about 3 cm/h.
  • step e) the rest of the liquid is removed from the layer if the removal of the liquid in step d) is incomplete.
  • the removal may be performed by heating and/or by reducing pressure without being restricted thereto.
  • the film can be annealed after deposition by heating the layer close to the melting point of the polymeric compound(s). By annealing the performance of some semiconducting layers may be enhanced.
  • the process according to the present invention can be used for manufacturing all kinds of microelectronic structures.
  • the process is particularly useful for manufacturing field effect transistors, photovoltaic devices, diodes, organic light emitting diodes (OLEDs), etc., without being restricted thereto.
  • All cited reference documents are incorporated herein by reference. All compositions are given by weight in relation to the whole mixture except otherwise indicated.
  • the semiconducting compound used in the following examples was 1 MH represented by the following chemical formula:
  • the transistors were fabricated on PET films with S/D structures of 100 micron channel length patterned from PEDOT:PSS.
  • the semiconductors were deposited by dipcoating.
  • the substrates were dipcoated by dipping them into the liquid comprising the semiconductor material and withdrawing them from the liquid at a rate of 24 mm/h.
  • identical samples were spincoated at 3000 rpm for 30 s.
  • Polyvinylalcohol was dissolved in water to obtain a solution containing 15 % by weight polyvinylalcohol and the solution was adjusted for film formation by adding 5 % by vol. of butylglycol.
  • the dielectric was spincoated from the solution at 3000 rpm for 30 s.
  • the gate electrode was formed by applying silver paint over the dielectric layer.
  • Table 1 Mobilities (averaged over 100 transistors)

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Thin Film Transistor (AREA)
  • Liquid Deposition Of Substances Of Which Semiconductor Devices Are Composed (AREA)

Abstract

A method for depositing a semiconducting layer comprising: a) providing a substrate having a surface; b) providing a mixture comprising one or more semiconducting compounds and one or more polymeric insulating compounds in a liquid; c) bringing at least part of the surface into contact with the mixture; d) moving a zone of the mixture being in contact with the surface along the surface in a moving direction, said zone providing a concentration gradient in the moving direction by evaporating at least part of the solvent; and e) if necessary, removing the non-evaporated part of the solvent.

Description

Method for depositing a semiconducting layer from a liquid
The present invention relates to a process for depositing a semiconducting layer comprising one or more semiconductor compounds and one or more polymeric compounds in a solvent on a substrate.
It is known, e. g. from J. Appl. Phys, 93, No. 10, 6137 (2003) or from Synthetic Metals 156 815 - 823 (2006), that the mobility of polymeric semiconducting layers like polythi- phene layers may be increased by using depositing methods like dip coating which are slow enough to allow some orientation of the polymer chains of the semiconducting compound.
Normally low molecular semiconducting compounds like monomers or oligomers show much better mobility than higher molecular weight polymeric compounds, which, how- ever, often suffer from bad processing performance. It was therefore tried to combine the advantage of the low molecular weight semiconducting compounds with the good processing of polymer compounds.
When blending polymeric semiconductors like polythiophenes with high molecular po- lystyrene as described in WO 2005/024895 or with polymethyl methacrylate as described in J. Macromolec. Sci. Part C: Polymer Revies, 46, 103 - 125 (2006) a vertical phase segregation into a semiconducting layer and a insulating layer is observed. Two layers, a semiconducting layer and an insulating layer can be deposited in a one step process.
It is further known to blend small amounts of low molecular weight semiconductors like rubrenes (Nature Materials 4, 601 (2005)) or polythiophenes (Nature materials 5, 950 (2006)) with a high molecular weight insulating polymer like atactic or isotactic polystyrene, polyethylene or polypropylene to produce semiconducting layers having good mobility and good processing performance. In case of Nature materials 5, 950 (2006) the blends were deposited by casting the blend from solution onto a heated hexame- thyldisilazane-treated Si-Siθ2 substrate comprising patterned gold source and drain electrodes to form an FET.
However, there is still a need for improvements of the mobility of the blends comprising a semiconductor and an insulating high molecular polymer. Further the prior art depositing methods often suffer from high fluctuations in the mobility of the semiconducting layers forming the transistors.
An object of the present invention is therefore a method for depositing a semiconducting layer comprising a low molecular weight semiconducting compound a high molecu- lar weight insulating polymer compound of better mobility and decreased fluctuations and wastage.
According to an aspect of the present invention a method is provided, the method comprising the steps:
a) providing a substrate having a surface; b) providing a mixture comprising one or more semiconducting compounds and one or more polymeric insulating compounds in a liquid; c) bringing at least part of the surface into contact with the mixture; d) moving a zone along the surface in a moving direction, said zone providing a concentration gradient in the moving direction by evaporating at least part of the solvent, and e) if necessary, removing the non-evaporated part of the solvent.
Surprisingly, when a transistor is formed according to the method of the present invention a very good reproducibility and uniformity in the mobilities and on/off ratios is observed. Against this, if the small molecule is used without the polymer, there is a big scatter in the results, with a high failure rate also (no FET characteristics).
Since the output of the circuit is constrained by the transistor with lowest mobility one of the major advantages is that electronic circuitry, particularly ring oscillators, prepared according to the process of the present invention has very low fluctuations in the mobility.
According to step a) of the present invention a substrate comprising a surface on which a semiconducting layer is to be deposited is provided. The substrate may be made of any material and may be of any shape if its function to support the semiconducting layer and other layers is not hindered. Preferably the substrate has the form of films or sheets which may be easily manufactured by extrusion processes if polymers are used.
The substrate may be formed from organic materials like organic polymers or inorganic materials like Si or metals. Preferably the substrate comprises a polymer selected from the group consisting of polyethylene therephthalate (PET), polyethylene naphthalate (PEN), polyimine (Pl), and the like without being restricted thereto. Particularly preferably the substrate is an organic polymer film.
In a preferred embodiment the surface comprises at least one source and drain electrode or at least one gate electrode.
In step b) of the present invention a mixture comprising one or more semiconducting compounds and one or more polymeric compounds in a liquid is provided. In a preferred embodiment the semiconducting compound(s) are monomeric or oli- gomeric. According to the present invention monomeric or oligomeric means that there are only one or up to about 20 repeating units in the molecule in (weight) average. Pre- ferably the semiconducting compound comprises 1 to 5 repeating units, most preferably the semiconducting compound is monomeric, dimeric or trimeric. Repeating units according to the present invention mean the part of the molecule repeating in identical form. Normally the repeating units correspond to the respective monomers.
The semiconducting compound may be a single compound or a mixture of compatible semiconducting compounds. Semiconducting compounds useful for the present invention are generally known in the art.
The organic semiconducting compound may be an n or p type.
Preferred semiconducting layers have a FET mobility of greater than 10"5 Cm2V-1S"1, more preferably greater than 10"4 Cm2V-1S"1, most preferably greater than 10"3 Cm2V-1S"1.
The organic semiconductor may be any conjugated aromatic molecule containing at least three aromatic rings. Preferred organic semiconductors contain 5, 6 or 7 mem- bered aromatic rings, especially preferred organic semiconductors contain 5 or 6 mem- bered aromatic rings.
Each of the aromatic rings may optionally contain one or more hetero atoms selected from Se, Te, P, Si, B, As, N, O or S, preferably from N, O or S.
The rings may be optionally substituted with alkyl, alkoxy, polyalkoxy, thioalkyl, acyl, aryl or substituted aryl groups, a fluorine atom, a cyano group, a nitro group or an optionally substituted secondary or tertiary alkylamine or arylamine -N(R3)(R4), where R3 and R4 each independently is H, optionally substituted alkyl, optionally substituted aryl, alkoxy or polyalkoxy groups. The alkyl and aryl groups may be optionally fluorinated.
The rings may be optionally fused or may be linked with a conjugated linking group such as -C(P)=C(T2)-, -C≡C-, -N(R')-, -N=N-, (R1J=N-, -N=C(R')-. T1 and T2 each inde- pendently represent H, Cl, F, -C≡N or lower alkyl groups particularly Ci-4 alkyl groups ; R' represents H, optionally substituted alkyl or optionally substituted aryl. The alkyl and aryl groups may be optionally fluorinated.
Other organic semiconducting compounds that can be used in this invention include compounds, oligomers and derivatives of compounds of the following list: Conjugated hydrocarbon polymers such as polyacene, polyphenylene, poly (phenylene vinylene), polyfluorene including oligomers of those conjugated hydrocarbon polymers ; condensed aromatic hydrocarbons such as anthracene, tetracene, chrysene, penta- cene, pyrene, perylene, coronen ; oligomeric para substituted phenylenes such as p- quaterphenyl (p-4P), p-quinquephenyl (p-5P), p-sexiphenyl (p-6P) ; conjugated heterocyclic polymers such as poly (3-substituted thiophene), poly (3, 4-bisubstituted thio- phene), polybenzothiophene, polyisothianapthene, poly(N-substituted pyrrole), poly (3- substituted pyrrole), poly (3, 4-bisubstituted pyrrole), polyfuran, polypyridine, poly-1 , 3, 4- oxadiazoles, polyisothianaphthene, poly(N-substituted aniline), poly (2-substituted aniline), poly (3-substituted aniline), poly (2, 3-bisubstituted aniline), polyazulene, polypyrene; pyrazoline compounds; polyselenophene; polybenzofuran; polyindole; polypyridazine; benzidine compounds; stilbene compounds; triazines; substituted met- allo- or metal-free porphines, phthalocyanines, fluorophthalocyanines, naphthalocya- nines or fluoronaphthalocyanines; C60 and C70 fullerenes; N, N'-dialkyl, substituted dialkyl, diaryl or substituted diary-1 , 4, 5, 8-naphthalenetetracarboxylic diimide and fluoro derivatives; N, N'- dialkyl, substituted dialkyl, diaryl or substituted diary 3, 4, 9, 10- perylenetetracarboxylicdiimide; bathophenanthroline; diphenoquinones; 1 , 3, 4- oxadiazoles; 1 1 , 11 , 12, 12-tetracyanonaptho-2, 6-quinodimethane; a, a'-bis (dithieno [3, 2-b2', 3'-d] thiophene); 2, 8-dialkyl, substituted dialkyl, diaryl or substituted diary anthradithiophene; 2, 2'-bibenzo [1 , 2-b : 4, 5-b'] dithiophene. Preferred compounds are those from the above list and derivatives thereof which are soluble.
A preferred class of semiconductors has repeat units of formula 1 :
Figure imgf000005_0001
Formula 1
where each Y1 is independently selected from P, S, As, N and Se and preferably pol- yarylamines, where Y1 is N ; Ar1 and Ar2 are aromatic groups and Ar3 is present only if Y1 is N, P, or As in which case it too is an aromatic group. Ar1, Ar2 and Ar3 may be the same or different and represent, independently if in different repeat units, a multivalent (preferably bivalent) aromatic group (preferably mononuclear but optionally polynu- clear) optionally substituted by at least one optionally substituted C1-40 carbyl-derived groups and/or at least one other optional substituent, and Ar3 represents, independently if in different repeat units, a mono or multivalent (preferably bivalent) aromatic group (preferably mononuclear but optionally polynuclear) optionally substituted by at least one : optionally substituted C1-40 carbyl-derived group and/or at least one other optional substituent ; where at least one terminal group is attached in the polymer to the Ar1, Ar2 and optionally Ar3 groups located at the end of the polymer chains, so as to cap the polymer chains and prevent further polymer growth, and at least one terminal group is derived from at least one end capping reagent used in the polymerisation to form said polymeric material to control the molecular weight thereof.
The number average degree of polymerisation is denoted by n and the number of the repeat units of Formula 1 which may be present per molecule in the invention may be from 2 to 1 , 000, preferably 3 to 100 and more preferably 3 to 20 inclusive. The polymer may comprise a mixture of different polymeric species of varying chain lengths and with a distribution of molecular weights (polydisperse) or consist of molecules of a sin- gle molecular weight (monodisperse).
The preferred polymeric materials are obtainable by polymerisation controlled by the addition of at least one end capping reagent in an amount sufficient to reduce substantial further growth of the polymer chain.
The asterisks extending from Ar1 and Ar2 in Formula 1 are intended to indicate that these groups may be multivalent (including divalent as shown in Formula 1).
Polymers may be further substituted with, on average, more than one aryl moiety which is further substituted with a moiety capable of chain extension or cross linking, for example by photopolymerisation or by thermal polymerisation. Such moities capable of chain extension are preferably hydroxy, glycidyl ether, acrylate ester, epoxide, methac- rylate ester, ethenyl, ethynyl, vinylbenzyloxy, maleimide, nadimide, trifluorovinyl ether, a cyclobutene bound to adjacent carbons on an aryl moiety or a trialkylsiloxy.
Other amine materials that may be useful in this invention are tetrakis (N, N-aryl) biary- idiamines, bis (N, N'-[substituted]phenyl) bis (N, N'-phenyl)-1 , 1- biphenyl-4, 4-diamines including 4-methyl, 2, 4-dimethyl and/or 3-methyl derivatives thereof, tetrakis (N, N- aryl) biphenyl-4, 4'-diamine-1 , 1-cyclohexanes and their derivatives, triphenylamine and its alkyl and aryl derivatives and poly (N-phenyl-1 , 4-phenyleneamine), N-dibenzo
[a,d]cycloheptene-5-ylidene-N',N'-di-p-tolyl-benzene-1 , 4-diamine, (9, 9-dimethyl- 9H- fluoroen-2-yl)-di-p-tolyl-amine and their derivatives.
Related materials, which may also find use in this invention have also been described in patent DE-A 36 10 649, EP-A 669 654, EP-A 765 106, WO 97/33193, WO 98/06773, US 5,677,096 and US 5,279,916.
Conjugated oligomeric and polymeric heterocyclic semiconductors may comprise a repeat unit of an optionally substituted 5 membered ring and terminal groups A1 and A2 as shown in Formula 2:
Figure imgf000007_0001
Formula 2
in which X may be Se, Te or preferably O, S, or -N(R)- where R represents H, option- ally substituted alkyl or optionally substituted aryl ; R1, R2, A1 and A2 may be independently H, alkyl, alkoxy, thioalkyl, acyl, aryl or substituted aryl, a fluorine atom, a cyano group, a nitro group or an optionally substituted secondary or tertiary alkylamine or arylamine -N(R3) (R4), where R3 and R4 are as defined above. The alkyl and aryl groups represented by R1, R2, R3, R4, A1 and A2 may be optionally fluorinated. The number of recurring units in the conjugated oligomer of Formula 2 is represented by an integer n, n is defined as for Formula 1. In compounds of Formula 2 n is preferably 2 to 14. Preferred oligomers have X = S, R1 and R2 = H and A1 and A2 = optionally substituted C-ι-12 alkyl groups, examples of especially preferred compounds being A1 and A2 = n-hexyl and where n=4, alpha-omega-n-hexylquaterthienylene (alpha-omega 4T), n=5, alpha-omega-n- hexylpentathienylene (alpha-omega-5T), n=6, alpha-omega-n- hexyl- hexathienylene (alpha-omega-6T), n=7, alpha-omega-n- hexylheptathienylene (alpha- omega-7T), n=8, alpha-omega-n-hexyloctathienylene (alpha-omega-8T), and n=9, al- pha-omega-n-hexyinonathienylene (alpha-omega-9T).
Oligomers containing a conjugated linking group may be represented by Formula 3:
R2 R1 R2 R1
Formula 3
in which X may be Se, Te, or preferably O, S, or -N(R)-, R is as defined above; R1, R2, A1 and A2 as defined above for Formula 2. Linking group L represents -C(P)=C(T2)-, -C≡C-, -N(R')-, -N=N-, (R)=N-, -N=C(R)- with T1 and T2 defined as above.
The semiconducting channel may also be a composite of two or more of the same ty- pes of semiconductors. Furthermore, a p type channel material may, for example be mixed with n-type materials for the effect of doping the layer. Multilayer semiconductor layers may also be used. For example the semiconductor may be intrinsic near the insulator interface and a highly doped region can additionally be coated next to the intrinsic layer. In a preferred embodiment of the present invention the one or more semiconductor compounds have a molecular weight of 1000 g/mol or less, in particular 500 g/mol or less. In a further embodiment the one or more semiconductor compounds are monomeric or oligomeric organic compounds with up to ten monomeric units, particularly with up to five monomeric units.
It is particularly preferred if the one or more semiconductor compounds are selected from the group consisting of substituted thiophenes, thiophene phenylene co- oligomers, polyacenes or polyheteroacenes, particularly pentacenes, or fluorenes, preferably in monomeric or oligomeric form.
The mixture of the present invention comprises one or more polymeric compounds. The polymeric compound(s) may be a single compound or a mixture of compounds and may be made of insulating and/or semiconducting compound(s). In a preferred embodiment the one or more polymeric compound(s) are insulators. Generally, all insulating polymers like isotactic or atactic polystyrene, polyethylene, particularly polyethylene having a density of 0,93 g/cm3 or more, polypropylene can be used.
The mixture may contain further organic or inorganic compounds, however, it is preferred that the solution essentially consists of the one or more semiconducting compounds and the one ore more polymeric compounds. It is particularly preferred to have a mixture essentially consisting of a single semiconducting compound and a single polymeric compound.
The mixture may be provided in form of a homogene mixture, e. g. a solution, or a het- erogene mixture, e.g. an emulsion, suspension or dispersion. A solution of the semiconducting and the polymeric compound is preferred.
The liquid may be a single compound or a mixture of compounds capable of solving or suspending the semiconducting compound and the polymeric compound under the process conditions. Preferred liquids are toluene, THF and halogenated aromatics like dichlorobenzene, or mixture thereof, without being restricted thereto.
The viscosity of the liquid comprising the semiconducting compound can easily be adjusted by the ratio of the semiconducting compound to the polymeric compound in the solution and the amount of liquid used. Preferred ratios of the semiconducting compound to the polymeric compound in the mixture are 99/1 (by weight) to 1/99, more preferably 90/10 to 10/90, most preferably 70/30 to 30/70. In solution, preferred concentrations of the semiconducting compound in the liquid are less than 10 % by weight, more preferably 0.5 to 7.5 % by weight, most preferably 1 to 5 % by weight. In step c) at least part of the surface is brought into contact with the solution. Depending on the deposition method used the surface is brought into contact with the solution either completely or preferably only in the region of the moving zone.
Then in step d) a zone of the mixture being in contact with the surface is moved along the surface in the moving direction.
In the zone at least part of the solvent is evaporated. The evaporation causes a concentration gradient along the moving direction. This concentration gradient must gen- erally be high enough, i.e. the evaporation must be fast enough to sufficiently remove the solvent from the solution to form a deposit of the semiconductor/polymer blend on the surface of the substrate. The content of remaining solvent in the deposited semiconducting layer depends on the thickness of the deposited layer and on the properties of the polymer like molecular weight. Preferably the content is less than 20 %, more preferably less than 10%, most preferably less than 5 %.
In a preferred embodiment the dimension (width) of the zone in moving direction is much shorter that the dimension (width) of the substrate to be coated with the semiconducting layer. The perpendicular dimension (length) is preferably of the order of the dimension of the substrate (length).
When producing Field Effect Transistors (FETs) the moving can be performed in two orientations, one where the source and drain electrodes are parallel to the moving direction of the foil, or where the source and drain structures are oriented perpendicular to said moving direction. Preferred is the perpendicular direction.
The velocity of moving is generally dependent on the removing rate of the solvent. Solvents having high boiling temperatures are generally less useful since the removal rate of the solvent at normal pressure will be too low. On the other hand, when using low boiling solvents the solvents evaporate to fast to allow any alignment of the polymer in the moving zone. Preferably the boiling temperature (NTP) is from 50 -C to 210 -C, more preferably from 60 -C to 180 -C, most preferably from 65 -C to 1 10 -C.
Steps c) and d) may be performed at room temperature or at elevated temperature. In one embodiment at least part, preferably the whole surface of the substrate is heated when depositing the semiconducting layer, e.g. from the backside of the substrate to speed up the evaporation of the solvent. In an alternative embodiment the moving zone itself may be heated, e.g. by radiation to cause or speed up evaporation of the solvent.
In one embodiment step d) is performed by drawing the substrate out of the solution. In this case the whole surface of the substrate is brought into contact with the liquid comprising the semiconducting compound and the polymeric compound and then slowly taken out of the liquid to ensure that at least part, preferably 50 %, more preferably 70 %, more preferably 80 %, more preferably 90 %, most preferably 95 % of the liquid are evaporated in the zone. Generally the zone width until the liquid content in the deposited semiconducting layer is below 5 % is below 10 mm, preferably about 1 mm to about 7 mm, most preferably about 1 mm to about 5 mm. In relative terms the zone width until the liquid content in the deposited layer is below 5 % in relation to the whole width of the substrate is generally about 0.5 % to about 20 %, preferably about 1 % to about 10 %, most preferably about 1 % to about 5 %. Generally the time for taking the substrate out of the liquid is depending on the liquid, particularly on the boiling point of the liquid. The speed is preferably about 0.2 cm/h to about 10 cm/h, more preferably about 1 cm/h to about 4 cm/h, most preferably about 2 cm/h to about 3 cm/h.
In another embodiment step d) is performed by casting the solution over the substrate. In this case only the area of the zone at one end of the substrate is brought into contact with the liquid comprising the semiconducting compound and the polymeric compound and then the zone is slowly moved across the substrate to the other end and thereby cast with the mixture. At least part, preferably 50 %, more preferably 70 %, more preferably 80 %, more preferably 90 %, most preferably 95 % of the liquid are evaporated in the zone. Generally the zone width until the liquid content in the deposited semicon- ducting layer is below 5 % is below 10 mm, preferably about 1 mm to about 7 mm, most preferably about 1 mm to about 5 mm. In relative terms the zone width until the liquid content in the deposited layer is below 5 % in relation to the whole width of the substrate is generally about 0.5 % to about 20 %, preferably about 1 % to about 10 %, most preferably about 1 % to about 5 %. Generally the time for taking the substrate out of the liquid is depending on the liquid, particularly on the boiling point of the liquid. The speed is preferably about 0.2 cm/h to about 10 cm/h, more preferably about 1 cm/h to about 4 cm/h, most preferably about 2 cm/h to about 3 cm/h.
In an optional step e) the rest of the liquid is removed from the layer if the removal of the liquid in step d) is incomplete. The removal may be performed by heating and/or by reducing pressure without being restricted thereto.
Optionally, the film can be annealed after deposition by heating the layer close to the melting point of the polymeric compound(s). By annealing the performance of some semiconducting layers may be enhanced.
The process according to the present invention can be used for manufacturing all kinds of microelectronic structures. The process is particularly useful for manufacturing field effect transistors, photovoltaic devices, diodes, organic light emitting diodes (OLEDs), etc., without being restricted thereto. All cited reference documents are incorporated herein by reference. All compositions are given by weight in relation to the whole mixture except otherwise indicated.
In the following the present invention is described by way of examples without restrict- ing the invention to the examples.
Examples
The semiconducting compound used in the following examples was 1 MH represented by the following chemical formula:
Figure imgf000011_0001
The transistors were fabricated on PET films with S/D structures of 100 micron channel length patterned from PEDOT:PSS.
4 g of 1 MH and atactic polystyrene (average molecular weight Mw=2 x 106 g/mol) as the insulating polymer compound were dissolved in 100 ml tetrahydrofuran to obtain a homogeneous solution. The relative amounts of 1 MH and PS (% by weight) were varied as indicated in table 1.
The semiconductors were deposited by dipcoating. The substrates were dipcoated by dipping them into the liquid comprising the semiconductor material and withdrawing them from the liquid at a rate of 24 mm/h. For comparison, identical samples were spincoated at 3000 rpm for 30 s.
Polyvinylalcohol was dissolved in water to obtain a solution containing 15 % by weight polyvinylalcohol and the solution was adjusted for film formation by adding 5 % by vol. of butylglycol. The dielectric was spincoated from the solution at 3000 rpm for 30 s.
To complete the transistor, the gate electrode was formed by applying silver paint over the dielectric layer.
The resulting semiconductor mobilities are shown in table 1. Table 1 : Mobilities (averaged over 100 transistors)
Figure imgf000012_0001
From the standard deviation it can be seen that the semiconducting layers of the transistors being prepared according to the present invention shows increased mobility and much lower fluctuations in the mobility than those prepared according to the prior art.

Claims

Claims
1. A method for depositing a semiconducting layer comprising:
a) providing a substrate having a surface; b) providing a mixture comprising one or more semiconducting compounds and one or more polymeric insulating compounds in a liquid; c) bringing at least part of the surface into contact with the mixture; d) moving a zone of the mixture being in contact with the surface along the surface in a moving direction, said zone providing a concentration gradient in the moving direction by evaporating at least part of the solvent; and e) if necessary, removing the non-evaporated part of the solvent.
2. The method as claimed in claim 1 , wherein the one or more semiconductor com- pounds have a molecular weight below 5000 g/mol, in particular below 1000 g/mol.
3. The method as claimed in claim 1 or 2, wherein the one or more semiconductor compounds are monomeric or oligomeric organic compounds with up to ten monomeric units, particularly with up to five monomeric units.
4. The method as claimed in any one of claims 1 to 3, wherein the one or more semiconductor compounds are selected from the group consisting of substituted thiophenes, thiophene phenylene co-oligomers, polyacenes, polyheteroacenes, or fluorenes.
5. The method as claimed in any one of claims 1 to 4, wherein the one or more polymeric compounds are insulators.
6. The method as claimed in claim 5, wherein the polymeric insulator compound is selected from the group consisting of isotactic or atactic polystyrene, polyethylene, particularly polyethylene having a density of 0,93 g/cm3 or more, polypropylene, or mixtures thereof.
7. The method as claimed in claims 1 to 6, wherein the surface comprises at least one source and drain electrode or at least one gate electrode.
8. The method as claimed in claims 1 to 7, wherein the solvent has a boiling point at normal pressure of from 60 0C to 180 0C, in particular from 65 0C to 1 10 0C.
9. The method as claimed in claims 1 to 8, wherein the substrate is an organic polymer film.
10. The method as claimed in claims 1 to 9, wherein step d) is performed by drawing the substrate out of the solution.
1 1. The method as claimed in claims 1 to 9, wherein step d) is performed by casting the solution over the substrate.
12. A method for producing a semiconducting device comprising field effect transistors comprising a method as claimed in any one of the preceding claims.
PCT/EP2008/059767 2007-07-30 2008-07-25 Method for depositing a semiconducting layer from a liquid WO2009016107A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP07113434.0 2007-07-30
EP07113434 2007-07-30

Publications (1)

Publication Number Publication Date
WO2009016107A1 true WO2009016107A1 (en) 2009-02-05

Family

ID=39968047

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2008/059767 WO2009016107A1 (en) 2007-07-30 2008-07-25 Method for depositing a semiconducting layer from a liquid

Country Status (2)

Country Link
TW (1) TW200929650A (en)
WO (1) WO2009016107A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8367717B2 (en) 2008-07-02 2013-02-05 Basf Se High performance solution processable semiconductor based on dithieno [2,3-D:2′, 3′-D′]benzo[1,2-B:4,5-B′] dithiophene
US8598304B2 (en) 2008-07-02 2013-12-03 Basf Se Poly(5,5′bis(thiophen-2-yl)-benzo[2,1-b;3,4-b′]dithiophene) and its use as high performance solution processable semiconducting polymer
US8877657B2 (en) 2009-04-28 2014-11-04 Basf Se Process for producing semiconductive layers
US9129801B2 (en) 2009-06-16 2015-09-08 Basf Se Thermally labile precursor compounds for improving the interparticulate contact sites and for filling the interstices in semiconductive metal oxide particle layers

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002045184A1 (en) * 2000-11-28 2002-06-06 Avecia Limited Field effect transistors and materials and methods for their manufacture
WO2003030278A2 (en) * 2001-10-01 2003-04-10 Koninklijke Philips Electronics N.V. Composition, method and electronic device
WO2005055248A2 (en) * 2003-11-28 2005-06-16 Merck Patent Gmbh Organic semiconducting layer formulations comprising polyacenes and organic binder polymers

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002045184A1 (en) * 2000-11-28 2002-06-06 Avecia Limited Field effect transistors and materials and methods for their manufacture
WO2003030278A2 (en) * 2001-10-01 2003-04-10 Koninklijke Philips Electronics N.V. Composition, method and electronic device
WO2005055248A2 (en) * 2003-11-28 2005-06-16 Merck Patent Gmbh Organic semiconducting layer formulations comprising polyacenes and organic binder polymers

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
VERILHAC ET AL: "Effect of macromolecular parameters and processing conditions on supramolecular organisation, morphology and electrical transport properties in thin layers of regioregular poly(3-hexylthiophene)", SYNTHETIC METALS, ELSEVIER SEQUOIA, LAUSANNE, CH, vol. 156, no. 11-13, 1 June 2006 (2006-06-01), pages 815 - 823, XP005583497, ISSN: 0379-6779 *
WANG GUANGMING ET AL: "Increased mobility from regioregular poly(3-hexylthiophene) field-effect transistors", JOURNAL OF APPLIED PHYSICS, AMERICAN INSTITUTE OF PHYSICS. NEW YORK, US, vol. 93, no. 10, 15 May 2003 (2003-05-15), pages 6137 - 6141, XP012057799, ISSN: 0021-8979 *
WOJCIECH PISULA, ANOOP MERON, MICHAEL STEPPUTAT, INGO LIEBERWIRTH, UTE KOLB, ADAM TRACZ, HENNING SIRRINGHAUS, KLAUS MÜLLEN: "A Zone-Casting Technique for Device Fabrication of Field-Effect Transistors Based on Discotic Hexa-peri-hexabenzocoronene", ADVANCED MATERIALS, vol. 17, 22 March 2005 (2005-03-22), pages 684 - 689, XP002504781 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8367717B2 (en) 2008-07-02 2013-02-05 Basf Se High performance solution processable semiconductor based on dithieno [2,3-D:2′, 3′-D′]benzo[1,2-B:4,5-B′] dithiophene
US8598304B2 (en) 2008-07-02 2013-12-03 Basf Se Poly(5,5′bis(thiophen-2-yl)-benzo[2,1-b;3,4-b′]dithiophene) and its use as high performance solution processable semiconducting polymer
US8877657B2 (en) 2009-04-28 2014-11-04 Basf Se Process for producing semiconductive layers
US9129801B2 (en) 2009-06-16 2015-09-08 Basf Se Thermally labile precursor compounds for improving the interparticulate contact sites and for filling the interstices in semiconductive metal oxide particle layers

Also Published As

Publication number Publication date
TW200929650A (en) 2009-07-01

Similar Documents

Publication Publication Date Title
EP1459392B1 (en) Organic field effect transistor with an organic dielectric
Ni et al. Ambipolar Conjugated Polymers with Ultrahigh Balanced Hole and Electron Mobility for Printed Organic Complementary Logic via a Two‐Step C H Activation Strategy
KR101604102B1 (en) Derivatized fullerene-based dopants for organic semiconductors
EP1579518B1 (en) Improvements in and relating to organic semiconducting materials
EP3433884B1 (en) Diazirine containing organic electronic compositions and device thereof
US20100133518A1 (en) Gate insulating film forming agent for thin-film transistor
TWI644964B (en) Organic semiconducting formulation
WO2009016107A1 (en) Method for depositing a semiconducting layer from a liquid
Abd Wahab et al. Charge Carrier Mobility of Organic Thin Film Transistor: Intrinsic and Extrinsic Influencing Factors Based on Organic Semiconducting Materials
WO2003065409A2 (en) Semiconductor film and process for its preparation
US10862040B2 (en) Methods and compositions for enhancing processability and charge transport of polymer semiconductors and devices made therefrom
Pospiech et al. Self-organizing semifluorinated polymers for organic electronics
Pandey Controlling the Orientation of Semiconducting Polymers in Floating Film for Anisotropic Charge Transport in Organic Field Effect Transistor
US9525135B2 (en) Thixotropic composition
KR20200089058A (en) Composition comprising water for bi-phasic dip-coating techniques and method for forming semiconducting polymer thin films using thereof
Solomeshch c12) United States Patent

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 08786428

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 08786428

Country of ref document: EP

Kind code of ref document: A1