Classifications

• • 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 a potential-jump barrier or a surface barrier
  • H10K10/40—Organic transistors
  • H10K10/46—Field-effect transistors, e.g. organic thin-film transistors [OTFT]
  • H10K10/462—Insulated gate field-effect transistors [IGFETs]
  • H10K10/468—Insulated gate field-effect transistors [IGFETs] characterised by the gate dielectrics
  • H10K10/471—Insulated gate field-effect transistors [IGFETs] characterised by the gate dielectrics the gate dielectric comprising only organic materials
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/54—Silicon-containing compounds
  • C08K5/541—Silicon-containing compounds containing oxygen
  • C08K5/5415—Silicon-containing compounds containing oxygen containing at least one Si—O bond
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
  • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
  • H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes

Definitions

• OTFTs organic thin-film transistors
• RFID radiofrequency identification
• OTFTs Although various polymers have been employed as dielectrics for OTFTs, two major limitations with current-generation polymeric dielectric-based OTFTs exist. First, OTFTs function at relatively large operating voltages due to the intrinsically low (compared to crystalline semiconductors) semiconductor charge carrier mobilities. Second, because very few polymeric dielectric materials can perform optimally with a wide range of both hole-transporting (p-type) and electron- transporting (n-type) organic semiconductors, there has been limited complementary circuit application. These problems are exacerbated when printed dielectric/circuits are fabricated.
• G ⁇ — (Eq. 2), where k is the dielectric constant, SQ is the d vacuum permittivity, and d is the thickness of the dielectric material, Cj is increased when k increases and/or d decreases.
• k of most insulating polymers is low ( ⁇ 3—6). Additionally, most insulating polymers need to be quite thick (usually ⁇ 1 ⁇ m) to avoid considerable current leakage through the gate electrode.
• polymeric dielectrics such as crosslinked melamine/Cr 6+ salts-polyvinylphenol (PVP) and crossl inked benzocyclobutene (BCB) have been introduced.
• PVP polyvinylphenol
• BCB crossl inked benzocyclobutene
• these polymer films require high annealing temperatures and C, values are typically « 20 nF cm "2 .
• the choice of dielectric material can affect ⁇ , which is an important device parameter.
• the gate dielectric permits the creation of the gate field and the establishment of the two-dimensional channel charge sheet. Upon application of a source-drain bias, the accumulated charges move very close to the dielectric-semiconductor interface from the source electrode to the drain electrode.
• the nature of the dielectric-semiconductor interface can greatly affect how these charges move within the semiconductor, i.e., the carrier mobility.
• the surface morphology of the dielectric material and variations in its surface energies have been shown to modify the growth, morphology, and microstructure of the vapor/solution-deposited semiconductor, each of these being a factor affecting ⁇ and I on ⁇ off t the latter being the drain-source current ratio between the "on" and "off states, another important device parameter.
• the properties of the dielectric material can also affect the density of state distribution for both amorphous and single-crystal semiconductors.
• dielectric materials that adhere well to diverse substrates, i.e., the dielectric materials do not delaminate easily, to ensure device integrity under operating conditions, and to have dielectric materials that are hydrophobic such that device performance is not affected by humidity.
• polymeric dielectric materials that can exhibit relatively high capacitance and low current leakage, that can be prepared from commercially available polymer/molecular precursors via solution processes at low temperatures and atmospheric pressures, that can be compatible with diverse gate materials and semiconductors, that can adhere well to various substrates, and that can be resistant to the absorption of ambient moisture.
• the present teachings provide dielectric materials and related precursor compositions and/or associated devices that address various deficiencies and shortcomings of the prior art, including some of those outlined above.
• the present teachings provide a precursor composition that includes in solution at least one of (i) a polymeric component and a crosslinker component, and (ii) a polymeric crosslinker that includes a pendant group having a thermally curable crosslinking moiety.
• the composition is adapted to form a dielectric material after crosslinking (e.g., by thermally curing) the precursor composition.
• the crosslinker component can include a thermally curable crosslinker having the formula: (X) 3-m (Y) m Si-Z-Si(Y) m (X)3-m
• the polymeric crosslinker can include a thermally curable crosslinking moiety having the formula:
• thermally curable crosslinkers of the present teachings can include [CH 3 C(O)O] 3 Si-(CH 2 ) 3 -O-(CH 2 ) 2 -O-(CH 2 )3-Si[CH3C(O)O]3 5 Cl 3 Si- (CH 2 ) 3 -O-(CH2)2-O-(CH 2 )3-SiCl3 J (CH3O)3Si-(CH2)2-phenyl-(CH 2 ) 2 -Si(OCH3)3, Cl 3 Si-(CH 2 )2-(CF2) 2 -(CH 2 ) 2 -SiCl3 J and [CH3C(O)O]3Si-(CH 2 ) 2 (CF2)2(CH 2 )2- Si[CH 3 C(O)O] 3 .
• the precursor composition can further include at least one of (in) a crosslinker component comprising a photochemically curable crosslinker and (iv) a photochemically curable polymeric crosslinker.
• a crosslinker component comprising a photochemically curable crosslinker and (iv) a photochemically curable polymeric crosslinker.
• photochemically curable crosslinkers typically include an alkenyl group (i.e., one or more double bonds), for example, an allyl group, a phenylethenyl group, or a cinnamoyl group.
• the polymeric component of the composition can include a polymer selected from a polyalkylene, a substituted polyalkylene, a siloxane polymer and a copolymer thereof.
• polyalkylenes and substituted polyalkylenes include, but are not limited to, polyethylenes, polypropylenes, polyvinylalcohols, polystyrenes, ring-functionalized derivatives of polystyrenes (e.g. polyvinylphenol (PVP)), and polyacrylates (e.g., polymethylmethacrylates (PMMA)).
• At least one of the polymeric component and the crosslinker component typically is dissolved in an anhydrous solvent.
• the anhydrous solvent can be selected from ethyl acetate, dioxane, bis(2-methoxyethyl) ether (diglyme), tetrahydrofuran, toluene, xylene, various alcohols including methanol and ethanol, and various ketones including acetone, cyclopentanone (CP), methylethylketone, and the like.
• the precursor composition can further include a metal oxide component, for example, to increase the dielectric constant (k) of a dielectric formed from the composition.
• the metal oxide component can be in particulate form and can be blended, mixed and/or incorporated in the composition.
• the metal oxide component can include a metal component selected from a Group I metal, a Group II metal, a Group III metal, a Group IV metal, a transition metal, and combinations thereof.
• the present teachings provide dielectric materials that include a crosslinked polymeric material that is a thermally cured product and/or a photochemically cured product of any of the precursor compositions described above.
• electronic devices that can incorporate one or more dielectric materials of the present teachings include, but are not limited to, organic thin film transistors (OTFTs) (e.g., organic field effect transistors (OFETs)) and capacitors.
• OFTs organic thin film transistors
• these devices can include, for example, a substrate component, a semiconductor component, and/or one or more metallic contact components.
• the present teachings provide various methods for preparing a dielectric material.
• the methods can include applying a precursor composition of the present teachings onto a substrate, and thermally curing the precursor composition (i.e., the coated substrate) to provide a dielectric material.
• the applying step can be performed by, for example, spin-coating, printing, spraying, or casting.
• the curing step can include heating at a temperature within a range of about 7O 0 C to about 15O 0 C in a high humidity atmosphere.
• the curing step can include exposing the precursor composition (i.e., the coated substrate) to ultraviolet light, e.g., by irradiation at a wavelength of about 245 nm.
• the curing step can include first heating at a temperature within a range of about 70 0 C and about 15O 0 C in a high humidity atmosphere, followed by irradiation with a wavelength of about 245 nm, or vice versa.
• the crosslinking reaction can be achieved by electron beam irradiation.
• Figure 1 is a schematic representation of different crosslinking strategies that can be employed using dielectric precursor compositions of the present teachings.
• Figure 2 A is a schematic representation of a crosslinking-patterning process, illustrating in order: depositing a dielectric precursor composition onto a substrate, photochemically curing the coated substrate, washing the dielectric/substrate composite, and heating the dielectric material to induce further crosslinking/patterning.
• Figure 2B includes optical and atomic force microscopy (AFM) micrographs of unpatterned (left) and patterned (right) embodiments of dielectric films of the present teachings.
• AFM optical and atomic force microscopy
• Figure 3 shows representative leakage current plots for several embodiments of dielectric films of the present teachings. Specifically, the films have a thickness between about 40 nm and 50 nm and were fabricated on doped silicon (Si) substrates using the polymer-crosslinker ratios listed in Table 1.
• Figure 4 shows representative leakage current plots for the same embodiments of dielectric films as Figure 3, except that they were fabricated on aluminium-polyethylene naphthalate (Al-PEN) and indium tin oxide (ITO)-glass substrates.
• Al-PEN aluminium-polyethylene naphthalate
• ITO indium tin oxide
• Figure 5 shows AFM images of several embodiments of dielectric films of the present teachings.
• the films in the top row were fabricated on top Si substrates and those in the bottom row were fabricated on bottom Al substrates.
• the ratios are polymerxrosslinker ratios, and a higher ratio indicates a higher polymer concentration and thus a thicker film.
• Figure 6 shows current-voltage (I- V) plots for several embodiments of dielectric films of the present teachings fabricated in capacitor structures.
• Figure 7 shows the transfer plots of several embodiments of OFETs of the present teachings (the present dielectric material on a silicon substrate (CPB-Si) and the present dielectric material on an aluminum substrate (CPB-Al)) and a comparative OFET having SiO 2 as the dielectric material.
• Figure 8 shows AFM images of a C ⁇ Cl-based dielectric film (A) and an EGO Ac-based dielectric film (B) 5 each prepared according to the present teachings.
• Figure 9 shows leakage current density vs voltage (J-V) plots (A) and leakage current density vs electric field (J-E) plots for thin dielectric films according to the present teachings prepared from precursor compositions including PVP and one of the following crosslinkers: C 6 Cl, C 6 OAc, EGOAc 3 and C 6 NMe 2 .
• FIG 10 shows the transfer plots of several embodiments of OFETs of the present teachings.
• the OFETs were fabricated with an ultra-thin dielectric film prepared from a precursor composition that includes PVP and one of the following crosslinkers: C O CI, C 6 OAc, EGOAc, and C 6 NMe 2 , and either a pentacene semiconductor layer (A) or a DFHC O-4T semiconductor layer (B).
• a precursor composition that includes PVP and one of the following crosslinkers: C O CI, C 6 OAc, EGOAc, and C 6 NMe 2 , and either a pentacene semiconductor layer (A) or a DFHC O-4T semiconductor layer (B).
• Figure 11 shows AFM images of various composites including a 50-nm thick pentacene film deposited on one of the following dielectric films: (A) PVP/C 6 C1 (6:6), (B) PVP/C 6 OAc (4:6), (C) PVP/EGOAc (4:6), (D) PVP/C 6 NMe 2 (4:6), and (E) PVP/F 4 C 5 C1 (4:4).
• Figure 12 provides AFM images of different gravure-printed dielectric films of the present teachings.
• Figure 13 provides optical images of dielectric films with vapor- deposited gold (Au) electrical contacts.
• Figure 14 is a plot of leakage current density versus applied bias for two embodiments of dielectric precursor compositions of the present teachings.
• Figure 15 shows a transfer plot (A) and an output plot (B) for a pentacene-OFET that includes a dielectric material of the present teachings.
• Figure 16 shows output plots for an OFET including a dielectric layer of the present teachings and an organic semiconductor layer prepared with N,N'-bis(n- octyl)-(l,7 and 1 ,6)-dicyanoperylene-3,4:9,10-bis(dicarboximide) (PDI-8CN 2 ) (A) 5 and an OFET including a dielectric layer of the present teachings and an organic semiconductor- layer prepared with bis(n-hexylphenyl)dithiophene (DH-PTTP) (B).
• PDI-8CN 2 N,N'-bis(n- octyl)-(l,7 and 1 ,6)-dicyanoperylene-3,4:9,10-bis(dicarboximide)
• DH-PTTP bis(n-hexylphenyl)dithiophene
• Figure 17 shows wide angle x-ray diffraction (WAXRD) spectra of composites including a 50 nm-thick semiconductor film (pentancene, PDI-8CN 2 , and DH-6T) vapor-deposited on a dielectric film of the present teachings.
• WAXRD wide angle x-ray diffraction
• Figure 18 provides a series of photographs of printed OFET devices of the present teachings.
• Figure 19 provides the transfer plots of two pentacene OFETs including gate dielectrics of the present teachings.
• the present teachings relate to dielectric materials and precursor compositions for preparing the same, as well as to electronic devices that include such dielectric materials.
• the present teachings provide crosslinked polymeric dielectric materials that can exhibit good insulating properties (e.g., with leakage currents in the order of ⁇ 10 '6 -10 "7 A/cm 2 ) and can be fabricated using low-temperature solution processes (e.g., spin-coating and printing). Solution-processed thin films ( ⁇ 300 nm) of the present dielectric materials can exhibit high mechanical flexibility and have very smooth surfaces.
• dielectric materials disclosed herein were found to adhere well to different substrates (e.g., gate materials such as doped silicon, aluminum, and indium tin oxide) and can be compatible with a wide range of ⁇ -type and n-type organic and inorganic semiconductors, making them attractive materials for fabricating various organic electronic ⁇ " ⁇ • example, organic thin film transistors (OTFTs) incorporating dielectric materials of the present teachings can operate at low biases, hence minimizing power consumption, particularly when the dielectric materials of the present teachings are in the form of ultra-thin films ( ⁇ about 50 nm), which can exhibit capacitance as high as ⁇ 300 nF cm "2 .
• substrates e.g., gate materials such as doped silicon, aluminum, and indium tin oxide
• the present teachings provide dielectric materials that include crosslinked polymeric matrices in which polymeric chains can be either covalently crosslinked by one or more thermally curable and/or photochemically curable crosslinkers, or embedded within or otherwise incorporated (e.g., mixed or blended) in a crosslinked matrix formed by the thermally curable and/or photochemically curable crosslinkers.
• These crosslinked polymeric matrices can be structurally robust and can exhibit good insulating properties.
• the present teachings also provide precursor compositions that can enable high-throughput fabrication (e.g., via fast and quantitative reactions under mild conditions) of such dielectric materials.
• compositions are described as having, including, or comprising specific components, or where processes are described as having, including, or comprising specific process steps, it is contemplated that compositions of the present teachings also consist essentially of, or consist of, the recited components, and that the processes of the present teachings also consist essentially of, or consist of, the recited processing steps.
• polymer or “polymeric compound” refers to a molecule including at least three or more repeating units connected by covalent chemical bonds.
• the polymer or polymeric compound can have only one type of repeating unit as well as two or more types of different repeating units.
• the term "copolymer” or “copolymeric compound” can be used herein instead, especially when the polymer includes chemically significantly different repeating units.
• the assembly of the repeating units in the copolymer can be head-to-tail, head-to-head, or taiL-to-tail.
• the copolymer can be a random copolymer, an alternating copolymer, or a block copolymer.
• the polymer can include one or more pendant groups.
• a "pendant group” refers to a moiety that is substituted on the backbone of a polymer.
• solution-processable refers to compounds, materials, or compositions that can be used in various solution-phase processes including spin- coating, printing (e.g., inkjet printing), spray coating, electrospray coating, drop casting, dip coating, and blade coating.
• alkoxy refers to -O-alkyl group. Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy (e.g., n-propoxy and isopropoxy), t-butoxy groups, and the like.
• alkyl refers to a straight-chain or branched saturated hydrocarbon group.
• alkyl groups include methyl (Me), ethyl (Et) 5 propyl (e.g., n-propyl and isopropyl), butyl (e.g., n-butyl, isobutyl, s-butyl, t-butyl), pentyl groups (e.g., n-pentyl, isopentyl, neopentyl), and the like.
• a lower alkyl group typically has up to 4 carbon atoms.
• lower alkyl groups include methyl, ethyl, propyl (e.g., n-propyl and isopropyl), and butyl groups (e.g., n-butyl, isobutyl, s-butyl, t-butyl).
• haloalkyl refers to an alkyl group having one or more halogen substituents.
• haloalkyl groups include CF 3 , C 2 Fs, CHF 2 , CH 2 F 1 CCl 3 , CHCl 2 , CH 2 Cl, C 2 Cl 5 , and the like.
• Perhaloalkyl groups i.e., alkyl groups wherein all of the hydrogen atoms are replaced with halogen atoms (e.g., CF 3 and C 2 Fs), are included within the definition of "haloalkyl.”
• a Ci -20 haloalkyl group can have the formula -C a X 2a +i- or
• X is F, Cl, Br, or I 3 a is an integer in the range of 1 to 20, and b is an integer in the range of 0 to 40, provided that b ⁇ 2a+l .
• arylalkyl refers to an —alkyl— aryl group, wherein the arylalkyl group is covalently linked to the defined chemical structure via the alkyl group.
• An arylalkyl group is within the definition of an -L-C 6 .14 aryl group, wherein L is as defined herein.
• An example of an arylalkyl group is a benzyl group (-CH 2 -CeHs).
• An arylalkyl group can be optionally substituted, i.e., the aryl group and/or the alkyl group can be substituted as disclosed herein.
• alkenyl refers to a straight-chain or branched alkyl group having one or more carbon-carbon double bonds.
• alkenyl groups include, but are not limited to, ethenyl, propenyl, butenyl, pentenyl, hexenyl, butadienyl, pentadienyl, hexadienyl groups, and the like.
• the one or more carbon- carbon double bonds can be internal (such as in 2-butene) or terminal (such as in 1- butene).
• cycloalkyl refers to a non-aromatic carbocyclic group including cyclized alkyl, alkenyl, and alkynyl groups.
• a cycloalkyl group can be monocyclic (e.g., cyclohexyl) or polycyclic (e.g., containing fused, bridged, and/or spiro ring systems), wherein the carbon atoms are located inside or outside of the ring system. Any suitable ring position of the cycloalkyl group can be covalently linked to the defined chemical structure.
• cycloalkyl groups include, but are not limited to, cyclopropyl, cyclopropylmethyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclohexylmethyl, cyclohexylethyl, cycloheptyl, cyclopentenyl, cyclohexenyl, cyclohexadienyl, cycloheptatrienyl, norbornyl, no ⁇ inyl, norcaryl, adamantyl, and spiro[4.5]decanyl groups, as well as their homologs, isomers, and the like.
• cycloalkyl groups can be substituted as disclosed herein.
• heteroatom refers to an atom of any element other than carbon or hydrogen and includes, for example, nitrogen, oxygen, sulfur, phosphorus, and selenium.
• cycloheteroalkyl refers to a non-aromatic cycloalkyl group that contains at least one ring heteroatom selected from O 3 N and S, and optionally contains one or more double or triple bonds.
• One or more N or S atoms in a cycloheteroalkyl ring may be oxidized (e.g., morpholine N-oxide, thiomorpholine S-oxide, thiomorpholine S,S-dioxide).
• nitrogen atoms of cycloheteroalkyl groups can bear a substituent, for example, a hydrogen atom, an alkyl group, or other substituents as described herein.
• Cycloheteroalkyl groups can also contain one or more oxo groups, such as piperidone, oxazolidinone, pyrimidine-2,4(lH,3H)-dione, pyridin-2(l ⁇ )-one, and the like.
• oxo groups such as piperidone, oxazolidinone, pyrimidine-2,4(lH,3H)-dione, pyridin-2(l ⁇ )-one, and the like.
• Examples of cycloheteroalkyl groups include, among others, morpholine, thiomorpholine, pyran, imidazolidine, imidazoline, oxazolidine, pyrazolidine, pyrazoline, pyrrolidine, pyrroline, tetrahydrofuran, tetrahydrothiophene, piperidine, piperazine, and the like.
• cycloheteroalkyl groups can be substituted as disclosed herein.
• aryl refers to an aromatic monocyclic hydrocarbon ring system or a polycyclic ring system in which two or more aromatic hydrocarbon rings are fused (i.e., having a bond in common with) together or at least one aromatic monocyclic hydrocarbon ring is fused to one or more cycloalkyl and/or cycloheteroalkyl rings.
• An aryl group can have from 6 to 14 carbon atoms in its ring system, which can include multiple fused rings.
• a polycyclic aryl group can have from 8 to 14 carbon atoms.
• aryl groups having only aromatic carbocyclic ring(s) include, but are not limited to, phenyl, 1 -naphthyl (bicyclic), 2-naphthyl (bicyclic), anthracenyl (tricyclic), phenanthrenyl (tricyclic) and like groups.
• polycyclic ring systems in which at least one aromatic carbocyclic ring is fused to one or more cycloalkyl and/or cycloheteroalkyl rings include, among others, benzo derivatives of cyclopentane (i.e., an indanyl group, which is a 5,6-bicyclic cycloalkyl/aromatic ring system), cyclohexane (i.e., a tetrahydronaphthyl group, which is a 6,6-bicyclic cycloalkyl/aromatic ring system), imidazoline (i.e., a benzimidazolinyl group, which is a 5,6-bicyclic cycloheteroalkyl/aromatic ring system), and pyran (i.e., a chromenyl group, which is a 6,6-bicyclic cycloheteroalkyl/aromatic ring system).
• aryl groups include, but are not limited to, benzodioxanyl, benzodioxolyl, chromanyl, indolinyl groups, and the like. In some embodiments, aryl groups can be substituted as disclosed herein.
• heteroaryl refers to an aromatic monocyclic ring system containing at least 1 ring heteroatom selected from oxygen (O), nitrogen (N) and sulfur (S) or a polycyclic ring system where at least one of the rings present in the ring system is aromatic and contains at least 1 ring heteroatom.
• Polycyclic heteroaryl groups include two or more heteroaryl rings fused together and monocyclic heteroaryl rings fused to one or more aromatic carbocyclic rings, non- aromatic carbocyclic rings, and/or non-aromatic cycloheteroalkyl rings.
• a heteroaryl group, as a whole, can have, for example, from 5 to 14 ring atoms and contain 1-5 ring heteroatoms.
• heteroaryl group can be attached to the defined chemical structure at any heteroatom or carbon atom that results in a stable structure. Generally, heteroaryl rings do not cont 3, or S-O bonds. However, one or more N or S atoms in a heteroaryl group can be oxidized (e.g., pyridine N-oxide, thiophene S-oxide, thiophene S,S-dioxide). Examples of heteroaryl groups include, for example, the 5-membered monocyclic and 5-6 bicyclic ring systems shown below:
• T is O, S, NH, N-alkyl, N-aryl, or N-(arylalkyl) (e.g., N-benzyl).
• heteroaryl rings include, but are not limited to, pyrrole, furan, thiophene, pyridine, pyrimidine, pyridazine, pyrazine, triazole, tetrazole, pyrazole, imidazole, isothiazole, thiazole, thiadiazole, isoxazole, oxazole, oxadiazole, indole, isoindole, benzofuran, benzothiophene, quinoline, 2-methylquinoline, isoquinoline, quinoxaline, quinazoline, benzotriazole, benzimidazole, benzothiazole, benzisothiazole, benzisoxazole, benzoxadiazole, benzoxazole, cinn
• heteroaryl groups include, but are not limited to, 4,5,6,7-tetrahydroindole, tetrahydroquinoline, benzothienopyridine, benzofuropyridine, and the like. In some embodiments, heteroaryl groups can be substituted as disclosed herein.
• substituents of compounds are disclosed in groups or in ranges. It is specifically intended that the description include each and every individual subcombination of the members of such groups and ranges.
• the term "Cue alkyl" is specifically intended to individually disclose Ci, C 2 , C 3 , C 4 , C ⁇ n ⁇ Ci-C 53 Ci-C 45 Ci-C 35 Ci-C 25 C 2 - C 6 , C 2 -C 5 , C 2 -C 4 , C 2 -C 3 , C 3 -C 6 , C 3 -C 5 , C 3 -C 4 , C 4 -C 6 , C 4 -C 5 , and C 5 -C 6 alkyl.
• an integer in the range of 0 to 40 is specifically intended to individually disclose 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, and 40, and an integer in the range of 1 to 20 is specifically intended to individually disclose 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20.
• phrases "optionally substituted with 1-5 substituents” is specifically intended to individually disclose a chemical group that can include 0, 1, 2, 3, 4, 5, 0-5, 0-4, 0-3, 0-2, 0-1, 1-5, 1-4, 1-3, 1-2, 2-5, 2-4, 2-3, 3-5, 3-4 3 and 4-5 substituents.
• the present teachings provide precursor compositions including one or more polymers (i.e., a polymeric component) and one or more crosslinking moieties or crosslinkers (i.e., a crosslinker component) which, upon crosslinking (e.g., by thermally curing or photochemically curing), can provide crosslinked polymeric . materials that are suitable for use as dielectric materials.
• the precursor composition can include the polymeric component and the crosslinker component as separate chemical moieties.
• the crosslinker component can include one or more crosslinkers that are small molecule compounds having one or more crosslinking groups.
• the polymeric component and the crosslinker component can be chemically combined in the form of a polymeric crosslinker, specifically, a polymer having one or more pendant crosslinking groups on its backbone.
• the precursor composition can include one or more solvents in which at least one of the polymeric component and the crosslinker component is substantially soluble.
• the crosslinker component of the precursor composition can include thermally curable crosslinkers that include two or more silyl groups.
• silyl groups can include one or more (e.g., one, two, or three) hydrolyzable moieties such as halo gro ⁇ roups, alkoxy groups, and carboxylate groups that can react with OH groups and induce crosslinking.
• the thermally curable crosslinkers can have the formula:
• m at each occurrence, is independently selected from 0, 1 , and 2;
• X 5 at each occurrence is independently selected from a halogen, -NR 1 R 2 , -OR 3 , and -OC(O)R 3 ;
• Y at each occurrence, is independently selected from H, a Ci -6 alkyl group, and a Cue haloalkyl group;
• Z is Q-W-Q
• Q at each occurrence, is independently selected from -L-, — O-, — O-L—, ' -L-O-,
• L at each occurrence, is independently a divalent C MO alkyl group or a divalent C 1 . io haloalkyl group, each of which is optionally substituted with 1-4 R 4 groups;
• W is selected from -SiXX-, -SiXY-, -SiYY-, -SiXX-O-, -O- SiXX-,
• R 1 and R 2 are independently selected from H 5 a Ci -6 alkyl group, a C 6- 14 aryl group, a 5-14 membered heteroaryl group, a -Ci -6 alkyl-C ⁇ - ⁇ aryl group, and a -Ci. 6 alkyl-5-14 membered heteroaryl group;
• R 3 is selected from H, a d. 6 alkyl group, a C
• R 4 and R 5 are independently selected from H, a halogen, a C]. 6 alkyl group, a C
• X at each occurrence, can be independently selected from Cl, OCH 3 , OCH 2 CH 3 , -N(CH 3 ) 2 - -N(CH 2 CH 3 ) 2 - -OC(O)CH 3 , and -OC(O)CH 2 CH 3 ; and Y, at each occurrence, can be independently selected from H, CF 3 , a methyl group, and an ethyl group.
• the thermally curable crosslinkers can be ⁇ , ⁇ -bisfunctionalized with SiX 3 groups, wherein X is selected from Cl, OCH 3 , OCH 2 CH 3 , -N(CHj) 2 - -N(CH 2 CH 3 ) 2 -, -OC(O)CH 3 , and - OC(O)CH 2 CH 3 .
• X is selected from Cl, OCH 3 , OCH 2 CH 3 , -N(CHj) 2 - -N(CH 2 CH 3 ) 2 -, -OC(O)CH 3 , and - OC(O)CH 2 CH 3 .
• the linker Z as defined above, can exclude certain combinations of Q— W-Q.
• Z cannot be — O— , a divalent Ci -2O alkyl group, or a covalent bond.
• Z can be a divalent linker that can be symmetrical or asymmetrical.
• Q at each occurrence, can be independently selected from -O-, a div lkyl group (e.g., -(CH 2 ) ⁇ -), a divalent Ci-io haloalkyl group (e.g.,
• W can be selected from -O-[(CR 4 2 ) t -O] p - [(CR 5 2 ),-O] q - (e.g., -O-[(CH 2 ) 2 -O]r- and -O-[(CF 2 ) 2 -O] t -), a divalent phenyl group, and a covalent bond, wherein R 4 and R 5 can be independently H or F, and p, q, and t are as defined herein.
• Z can be an alkylene glycol linker.
• Z can be Q— W— Q, wherein Q, at each occurrence, is independently a divalent Ci -6 alkyl group or a covalent bond, and W is — O— ⁇ [(CH 2 ) 3 -O]p-[(CH 2 ) 2 -O] q ⁇ - wherein p is 0, 1, 2, 3, 4, 5 or 6, and q is 1, 2, 3, 4, 5 or 6.
• Crosslinkers according to the formula given above include, but are not limited to,
• Z can include one or more -Q-Si(Y) 01 (X) 3-01 substituents to provide additional groups for crosslinking.
• Z can be Q-W-Q, wherein Q, at each occurrence, can be independently a divalent C i.io alkyl group or a divalent Ci.
• io haloalkyl group, and W can be selected from — O-[(CR 4 2 )t- O] p -[(CR 5 2)r O] q - and a divalent phenyl group, wherein the divalent C MO alkyl group, the divalent Ci-io haloalkyl group, and the divalent phenyl group can be substituted with 1-4 -Q-Si(Y) m (X)3-m groups (thereby creating a higher order valency group, e.g., a trivalent or tetravalent phenyl group), R 4 and R 5 can be independently H, F, or -Q-Si(Y) m (X) 3-m , and Q, X 3 Y, m 3 p, q, and t are as defined herein.
• a non-limiting example of these embodiments is a crosslinker having the formula:
• the precursor composition can include a polymeric crosslinker, i.e., a polymer having one or more crosslinking pendant groups.
• the pendant group can include a thermally curable crosslinking moiety having the formula:
• the thermally curable polymeric crosslinker can have the formula:
• R 6 at each occurrence, is independently H, a halogen, or a Ci -6 alkyl group
• R 7 is selected from H, OH, a halogen, C(O)O-R 3 , a Ci -6 alkyl group, a C
• R at each occurrence, can be H or a methyl group;
• R 7 can be selected from H, OH 3 a methyl group, C(O)O-Ci -6 alkyl, and a phenyl group optionally substituted with OH or — O— Ci -6 alkyl;
• R 8 can be selected from — O— , — C(O)O-, a divalent Ci -4 alkyl group, and a divalent phenyl group;
• Q can be selected from -L-, -O-L— , and a covalent bond, wherein L is as defined herein.
• a non-limiting example of such a thermally curable polymeric crosslinker is
• Ac is an acetyl group (i.e., CHaC(O)-), and x and y are as defined herein.
• crosslinking reactions with these thermally curable crosslinkers typically rely on the fast and quantitative coupling reactions of the functional groups (e.g., the one or more halo groups, alkoxy groups, amino groups, and carboxylate groups) on the silicon with water and/or the hydroxyl group(s) of a OH-functionalized molecule or polymer to produce a robust siloxane network.
• the functional groups e.g., the one or more halo groups, alkoxy groups, amino groups, and carboxylate groups
• one or more photochemically curable crosslinkers can be utilized alone or in conjunction with one or more thermally curable crosslinkers.
• Such photochemically cu nkers are well known in the art and typically include an alkenyl group (i.e., one or more double bonds), for example, an allyl group, a phenylethenyl group, or a cinnamoyl group.
• these photochemically curable crosslinkers are polymers that include one or more photochemically curable crosslinking groups.
• a photochemically curable polymeric crosslinker can have the formula:
• R 6 , R 7 , R 8 , Q 3 x and y are as defined herein.
• the crosslinking chemistry involving these photochemically curable crosslinkers can consist of a 2+2 photo-stimulated cycloaddition that provides stable cyclobutane moieties.
• the crosslinking chemistry can also involve free radical additions.
• the polymeric component of the precursor compositions described above can include various electrically non-conducting polymers, including those that have been used as dielectric materials. Examples include, but are not limited to, polyalkylenes, substituted polyalkylenes, siloxane polymers, and copolymers of polyalkylenes, substituted polyalkylenes, and/or siloxane polymers.
• polyalkylenes and substituted polyalkylenes can include, but are not limited to, polyethylenes (PE), polypropylenes (PP), polyvinylalcohols (PVA), polystyrenes (PS), ring-functionalized derivatives of polystyrenes (e.g., polyvinylphenols (PVP)), and polyacrylates (e.g., polymethylmethacrylates (PMMA)).
• PE polyethylenes
• PP polypropylenes
• PVA polyvinylalcohols
• PS polystyrenes
• PS ring-functionalized derivatives of polystyrenes
• PVP polyvinylphenols
• PMMA polymethylmethacrylates
• R 9 at each occurrence, is independently selected from H, a C
• the siloxane polymer can have the formula:
• the precursor compositions described above also can include a metal oxide component.
• the metal oxide component typically has a high dielectric constant (k). Therefore, the incorporation of such a metal oxide component into a precursor composition can help increase the dielectric constant of the resulting dielectric material.
• the metal oxide component can be in particulate form and can be blended, mixed and/or otherwise incorporated in the composition.
• the metal oxide component can include a metal component selected from a Group I metal, a Group II metal, a Group III metal, a Group IV metal, a transition metal, and combinations thereof.
• the various crosslinkers and polymers described above typically are somewhat soluble, and preferably highly soluble, in various solvents (e.g., various anhydrous solvents).
• the crosslinker component and the polymeric component can be dissolved in the same solvent or in different solvents before combining with each other to provide the precursor compositions of the present teachings.
• a compound can be considered soluble in a solvent when at least 1 mg of the compound is soluble in 1 mL of the solvent.
• Examples of common solvents include petroleum ethers; acetonitrile; aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; ketones such as acetone, cyclopentanone (CP) 5 methyl ethyl ketone, and 2-butanone; ethers such as tetrahydrofuran (THF), dioxane, bis(2-methoxyethyl) ether (diglyme), diethyl ether, di-isopropyl ether, and t-butyl methyl ether; alcohols such as methanol, ethanol, butanol, and isopropyl alcohol; aliphatic hydrocarbons such as hexanes; acetates such as methyl acetate, ethyl acetate (EtOAc), methyl formate, ethyl formate, isopropyl acetate; and halogenated aliphatic and aromatic hydrocarbons such as
• the precursor compositions are adapted to form dielectric materials that can exhibit a wide range of desirable properties and characteristics.
• the dielectric materials prepared from the precursor compositions described above can be very thin and pinhole-free, can have a high breakdown voltage and good long-term stability, can exhibit high capacitance and low current leakage, can show good adhesion to various substrates, and can be patterned using conventional techniques without delamination.
• the present dielectric materials also can demonstrate other advantageous characteristics such as, but not limited to, solution- processability, fabricability at low temperatures and/or atmospheric pressures, and compatibility with a diverse range of materials used in fabricating various electronic devices (e.g., thin film transistors, field-effect devices, organic light emitting diodes (OLEDs), organic photovoltaics, photodetectors, capacitors, and sensors).
• various electronic devices e.g., thin film transistors, field-effect devices, organic light emitting diodes (OLEDs), organic photovoltaics, photodetectors, capacitors, and sensors.
• a dielectric material in the form of a film using the precursor compositions of the present teachings various film deposition techniques can be used. These techniques include casting (e.g., drop-casting), dip coating, blade coating, spraying, printing, and spin-coating. Spin-coating involves applying an excess amount of a precursor composition (e.g., a solution of a polymeric component and a crosslinker component) onto a substrate, then rotating the substrate at high speed to spread the fluid by centrifugal force. The thickness and the surface morphology of the resulting dielectric d by this technique is dependent on the spin-coating rate, the concentration of the solution, as well as the solvent used.
• a precursor composition e.g., a solution of a polymeric component and a crosslinker component
• Printing can be performed, for example, with a rotogravure printing press, a flexo printing press, or an inkjet printer.
• the thickness of the dielectric film in these cases will similarly be dependent on the concentration of the solution, the choice of solvent, and the number of printing repetitions.
• Much of the printed electronics technology has focused on inkjet printing, primarily because this technique offers greater control over feature position and multilayer registration.
• InkJet printing is a noncontact process, which offers the benefits of not requiring a preformed master (compared to contact printing techniques), as well as digital control of ink ejection, thereby providing drop-on-demand printing.
• contact printing techniques have the key advantage of being well-suited for very fast roll-to-roll processing.
• Exemplary contact printing techniques include screen-printing, gravure, offset, and microcontact printing.
• the thickness of the dielectric materials of the present teachings can be controlled, and can be made as thin as 10 nm to several microns as established by profilometry and/or atomic force microscopy (AFM).
• dielectric films prepared according to the present teachings can have a thickness range from about 10 nm to about 20 nm and up to 10 ⁇ m or more. Films of greater thicknesses, if desired or required, can be obtained by 1) multiple spin-on depositions/printing repetitions before curing, as the dielectric materials of the present teachings can be stable to and not adversely affected by precursor or processing solutions; or 2) adjusting and/or increasing the polymer precursor concentration(s).
• dielectric films of the present teachings are relatively thin (e.g., less than about 300 nm), and in some embodiments, ultra-thin (e.g., less than about 50 nm or less than about 30 nm).
• crosslinked polymeric material can be a thermally cured product and/or a photochemically cured product of the precursor composition.
• the crosslinked polymeric material can be a thermally cured product and/or a photochemically cured product of the precursor composition.
• four different crosslinking strategies can be employed depending on the type and the order of the crosslinking chemistry. R figure 1, these processes include: /) thermal/high-humidity curing; H) photochemical curing; Ui) thermal/high- humidity curing followed by photochemical curing; and iv) photochemical curing followed by thermal/high-humidity curing.
• the thermal curing step can include annealing at an elevated temperature range in a high-humidity environment ( ⁇ 70%- 90% humidity) for a short period of time (e.g., 5-10 minutes), followed by dry curing (e.g., in a vacuum oven) at a similar temperature range for a longer period of time (e.g., 1-3 hours).
• the elevated temperature range can be from about 7O 0 C to about 150 0 C, from about 9O 0 C to about 14O 0 C, and from about 100 0 C to about 130 0 C.
• the photocuring step can include exposure to ultraviolet light (e.g., irradiation with a wavelength of about 245 run) for about 5-15 minutes depending on the thickness of the film.
• crosslinking also can be achieved by electron beam irradiation alone or in conjunction with one or both of the techniques discussed above.
• Crosslinked polymeric dielectric materials with different and/or complementary properties can be obtained using one or more of these processes.
• photochemically curable crosslinkers can facilitate patterning, for example, as demonstrated in the process illustrated in Figure 2.
• fabrication of a dielectric material can be performed in air (e.g., in a simple fume hood) in a controllable manner.
• Silane hydrolysis, condensation, and/or crosslinking typically occurs within seconds after deposition under ambient conditions.
• the process can be optimized by using controlled- atomosphere conditions during film deposition and annealing.
• the structural integrity of the resulting dielectric material can be evident by its insolubility in the mother solution.
• the curing temperatures typically lower than 130°C, are compatible with common plastic substrates employed in organic electronics such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN).
• PET polyethylene terephthalate
• PEN polyethylene naphthalate
• the crosslinking chemistry according to the present teachings can ensure strong adhesion to a substrate, for example, a bottom gate electrode, thus preventing delamination upon successive deposition and/or patterning of subsequent device layers, as well as during device operation.
• the present teachings further provide an article of manufacture, for example, a composite, that comprises a dielectric material of the present teachings and a substrate component and/or a semiconductor component.
• the substrate component can be selected from, but is not limited to, a doped silicon, an indium tin oxide (ITO), ITO-coated glass, ITO-coated mylar, aluminum, a doped polythiophene, and the like.
• the composite can include a semiconductor component.
• the semiconductor component can be selected from, but is not limited to, various fused heterocycles, polythiophenes, fused aromatics, and other such semiconductor compounds or materials, whether p-type or n-type, otherwise known or found useful in the art.
• the semiconductor component also can include inorganic semiconductor materials such as silicon, germanium, gallium arsenide, and the like.
• One or more of the composites described above can be embodied within an organic electronic device such as an OTFT, specifically, an OFET. Such an OFET can operate at low biases due to the high capacitance of the dielectric materials of the present teachings.
• dielectric materials were prepared and characterized by AFM, metal-insulator-metal (MIM) device and metal-insulator-semiconductor (MIS) device leakage and impedance spectroscopy measurements, to demonstrate, among other things, their compatibility with various p-type and n-type organic semiconductors.
• Organic electronic devices e.g., organic thin film transistors (OTFTs), specifically, organic field effect transistors (OFETs), based on these dielectric films also have been fabricated and characterized, data of which are provided below.
• Example 1 Preparation of l-trichlorosilanyI-3-[2-(3-trichlorosilanyl- propoxy)-ethoxy]-propane (EGCl) and l-triacetoxysiIanyl-3-[2-(3- triacetoxysilanyl-propoxy)-ethoxy]-propane (EGOAc)
• EVCl l-trichlorosilanyI-3-[2-(3-trichlorosilanyl-propoxy)-ethoxy]-propane
• EGOAc l-triacetoxysilanyl-3-[2-(3-triacetoxysilanyl-propoxy)-ethoxy]-propane
• Step 1 Preparation of 3 -(2-allyloxy-ethoxy)-propene
• Step 2 Preparation of l-t ⁇ chlorosilanyl-3-[2-(3-trichlorosilanyl- propoxy)-ethoxy] -propane (EGCl)
• Step 3 Preparation of l-triacetoxysilanyl-3-[2-(3-triacetoxysilanyl- propoxy)-ethoxy] -propane (EGOAc) [0101] Di(3-trichlorosilyl)propyl ethylene ether (10 g, 0.0242 mol) and acetic anhydride (27 mL, 0.048 mol) were slowly added to a 100 mL air-free flask. The reaction solution was stirred at 8O 0 C for 5 hours. Acetyl chloride was removed by distillation occasionally during the reaction.
• Example 3 Preparation of l,6-bis(trich!orosilyI)-3,3,4,4- tetrafluorohexane (F 4 CeCl) and l,6-bis(triacetoxysilyl)-3,3,4,4- tetrafluorohexane (F 4 C OAC)
• Scheme 2 depicts an exemplary synthetic route for the preparation of 1.6-bis(trichlorosilyl)-3 5 3 5 4,4-tetrafluorohexane (F 4 C 6 Cl) and 1 ,6- bis(triacetoxysi Iy l)-3 ,3 ,4,4-tetrafluorohexane (F 4 CeOAc).
• Step 1 Preparation of l,6-bis(trichlorosilyl)-3,3,4,4-tetrafluorohexane (F 4 C 6 Cl)
• Step 2 Preparation of l,6-bis(triacetoxysilyl)-3 5 3,4,4-tetrafluorohexane (F 4 C 6 OAc)
• Example 4 Preparation of poly [4-methoxystyrene-co-4-(3- triacetoxysilyl propoxystyrene))
• Scheme 3 depicts an exemplary synthetic route for the preparation of poly [4-methoxystyrene-co-4-(3-triacetoxysilylpropoxystyrene)] .
• Step 1 Preparation of poly[4-methoxystyrene-co-4-allyloxystyrene]
• Step 2 Preparation of poly[4-methoxystyrene-co-4-(3-triacetoxysilyl propoxystyrene)]
• Poly(4-methoxystyrene-co-4-allyloxystyrene) from Step 1 (1.0 gram), 3 mg of hydrogen hexachloroplatinate (IV) hydrate, and 30 mL dried THF were added to a 250-mL air-free flask with a condenser.
• Trichlorosilane (2 mL, 0.0198 mol) was added dropwise to the solution and the solution was subsequently heated in an oil bath of 8O 0 C.
• Scheme 4 below depicts an exemplary synthetic route for the preparation of poly(vinylphenol-co- 4-cinnamoylstyrene).
• Example 6 Surface morphology and dielectric properties of spin- coated ultrathin dielectric films prepared from precursor compositions containing bifunctionalized-silane crosslinkers
• precursor compositions were prepared nt combinations of various polymers, thermally curable crosslinkers, and solvents. These precursor compositions were subsequently spin-coated onto silicon substrates to provide ultrathin ( ⁇ 50 nm) dielectric films.
• Poly(4- vinyl phenol-co-styrene) [P(VP x -Sy)] was synthesized according to the procedures described in Lei et al. (2003), Macromolecules, 23: 5071-5074.
• PhOMe Hexachlorodisiloxane (C 0 Cl) and l,6-bis(trichlorosilyl)hexane (C 6 Cl) were purchased from Acros Organics (Geel, Belgium) and Gelest, Inc. (Morrisville, PA), respectively, and purified by distillation. l,12-Bis(trichlorosilyl)dodecane (Ci 2 Cl) was synthesized by hydrosilylation of commercially available 1,11- dodecadiene.
• 1,6-Bis(trimethoxysilyl)hexane (C 6 OMe) and 1,6- bis(triacetoxysilyl)hexane (C 6 OAc) were synthesized from the chloro precursors C 6 Cl.
• 1,4-Bis(trimethoxysilylethyl)benzene (PhOMe) was synthesized according to procedures described in Kabeta et al., J. Polym. Sci. A. Polym. Chem., 34(14): 2991- 2998 (1996).
• the solvents used were tetrahydrofuran (THF), dioxane, and ethyl acetate (AcOEt).
• the silicon substrates were highly n-doped silicon wafers obtained from Montco Silicon Tech, Inc. (Spring City, PA) and cleaned according to standard procedures, e.g., sonication in organic solvent, Pirahna solution, and oxygen plasma treatment, before use.
• Example 7 Insulating properties of of spin-coated ultrathin dielectric films prepared from precursor compositions containing bifunctionalized-silane crosslinkers
• Comparable leakage current densities were obtained using other gate substrates, specifically, Al-PEN and ITO-glass substrates.
• Al-PEN substrates were prepared according to literature reports; e.g., by sputtering aluminum (about 20-100 nm in thickness) on an Ch-plasma treated commercially-available PEN substrate.
• ITO-glass substrates were cleaned with an oxygen plasma before use. Representative leakage current-voltage plots are provided in Figure 4.
• Example 8 Surface morphology and dielectric characteristics of spin-coated dielectric films prepared from precursor compositions containing bifunctionalized-silane ethylene glycol crosslinkers
• Spin-coated dielectric films were prepared using thermally curable precursor compositions containing bifunctionalized triacetoxylated-silane ethylene glycol crosslinkers (EGOAc) following procedures described in Examples 1 and 6.
• EGOAc bifunctionalized triacetoxylated-silane ethylene glycol crosslinkers
• Ci PVP EGOAc (nm) (nF cm-2)
• Dielectric films prepared with bifunctionalized-silane ethylene glycol crosslinkers exhibited excellent surface smoothness, with an RMS roughness of about 0.3 nm to about 0.7 nm as demonstrated by the AFM images shown in Figure
• Example 9 Insulating properties of spin-coated dielectric films prepared from precursor compositions containing bifunctionalized-silane ethylene glycol crosslinkers
• Example 10 Device performance of OFETs fabricated with spin- coated dielectric films prepared from precursor compositions containing bifunctionalized-silane ethylene glycol crosslinkers
• Pentacene OFETs were fabricated with dielectric films of Example 8 on both silicon and aluminium gate materials.
• the silicon substrates were highly n-doped silicon wafers obtained from Montco Silicon Tech, Inc. (Spring City, PA) and cleaned according to standard procedures, e.g., sonication in organic solvent, Pirahna solution, and oxygen plasma treatment, before use.
• the aluminium substrates were cut from commercially available aluminium foil (Reynolds Wrap®).
• Pentacene was purchased from Sigma- Aldrich (St. Louis, MO) and vacuum- deposited at about 2 x 10 "6 Torr (500 A, 0.2 A/s) while maintaining the substrate temperature at about 5O 0 C to about 7O 0 C.
• Gold electrodes were vacuum-deposited through shadow masks at 3-4 x 10 '6 Torr (1000 A, 0.5 A/s).
• the channel length is 100 ⁇ m
• the channel width is 2000 ⁇ m.
• a comparative pentacene OFET device was fabricated using silicon oxide (SiO 2 ) as the dielectric material.
• the silicon oxide film has a thickness of 300 nm.
• the carrier mobilities of this comparative device was found to be about 0.1 cm 2 /Vs to about 0.3 cmVVs at larger operating voltages.
• Example 11 Surface morphology and dielectric properties of spin- coated thin dielectric films prepared from precursor compositions containing bifunctionalized-silane crosslinkers
• Thin dielectric films (about 50-300 ran) were prepared using precursor compositions employing PVP as the polymer and C 6 Cl, C 6 OAc, EGOAc, C 6 NMe 2 and F 4 CeCl 5 respectively as the crosslinker component.
• the precursor compositions were spin-coated on Si and flexible Al/PEN substrates following procedures described in Example 6. Table 3 summarizes the compositions of the precursor compositions, as well as the electrical and physical properties of the resulting dielectric films on Si substrates.
• Thin dielectric films fabricated with crosslinkers C 6 Cl and C 6 NMe 2 afford ⁇ 10 times higher leakage current densities ( ⁇ 1 x 10 '6 A/cm 2 ) compared to those fabricated with EGOAc and F 4 C 6 Cl ( ⁇ 1 x 10 "7 A/cm 2 ) at an electric field of 2 MV/cm.
• EGO Ac-based dielectric films also afford smoother film morphology (RMS ⁇ 0.2-0.3 nm) than C 6 Cl-based ( ⁇ 0.3-0.4 nm) or C 6 NMe 2 -based ( ⁇ 2-3 nm) films. While dielectric films fabricated with C 6 Cl show relatively smooth film morphology at a small area, the overall film morphology is not as smooth as
• EGO Ac-based films (Figure 8). Compared to films fabricated on Si substrates, dielectric films fabricated on Al/PEN substrates afford relatively rough surface morphologies (RMS ⁇ 0.5—0.6 nm) and higher leakage current densities ( ⁇ 1 x 10 "6 A/cm 2 ) at an electric field of 2 MV/cm. Representative leakage current-voltage plots are shown in Figure 9.
• Example 12 Fabrication and performance of thin film transistors using ultra-thin and thin spin-coated dielectric films
• Top-contact OFETs were fabricated with ultra-thin ( ⁇ 50 nm) and thin (about 50-300 nm) spin-coated dielect ' ⁇ * pared with PVP and a crosslinker selected from C 6 Cl 5 C 6 OAc 5 EGOAc, C 6 NMe 2 and F 4 C 6 Cl.
• Si and Al/PEN substrates were used, along with pentacene (P5) and 5,5"'-diperfluorohexylcarbonyI- 2,2':5',2":5",2 m -quaterthiophene (DFHCO-4T) as the p-type and n-type semiconductor, respectively.
• P5 was purchased from Sigma- Aldrich (St.
• DFHCO-4T were prepared and deposited as described in U.S. Patent Application Publication No. 2006/0186401, the disclosure of which is incorporated by reference in its entirety.
• Gold electrodes were vacuum-deposited through shadow masks at 3-4 x 10 "6 Torr (1000 A 5 0.5 A/s). The channel length is 100 ⁇ m, and the channel width is 2000 ⁇ m.
• Pentacene film FETs It has been reported with pentacene film FETs that rough gate dielectric surfaces afford smaller pentacene grains compared to very smooth substrates, leading to poorer FET performance. Grain boundaries between semiconductor crystallites are considered to be one type of interfacial charge trapping sites, which disrupt charge transport. Pentacene films grown on relatively smooth dielectric films fabricated with C 6 OAc and EGOAc afford large, dendritic grains (> 3 ⁇ m), while very small ( ⁇ 0.3 ⁇ m) pentacene grains are grown on C ⁇ Cl-based and C 6 NMe 2 -based dielectric films (see Figure 11).
• Example 13 Printability of dielectric precursor compositions containing thermally curable bifunctionalized-silane ethylene glycol crosslinkers.
• Example 5 Similar to the procedures described in Example 6, the polymer and the crosslinker were individually dissolved in solvent and combined at a specific volume ratio. The resulting formulation was gravure-printed (also can be flexo printed) onto freshly oxygen plasma-treated ITO-mylar or Al-PEN substrates. Table 5
• Example 14 Surface morphology of dielectric films printed from precursor compositions containing bifunctionalized-silane ethylene glycol crosslinkers.
• Figure 12 shows AFM micrographs of dielectric films printed from optimized precursor compositions containing bifunctionalized-silane ethylene glycol crosslinkers (see Tables 5 and 6). These micrographs demonstrate that the optimized printed dielectric films exhibit a very smooth surface which is a prerequisite for good OFET charge transport.
• Identifying the optimal composition of the dielectric precursor formulations is critical to achieve pinhole-free defect-free dielectric films.
• Figure 13 shows optical pictures of gravure-printed dielectric films fabricated using unoptimized and optimized formulations. It can be clearly seen that the film quality is significantly different, with the top film being extremely smooth and defect-free, and the bottom film exhibiting a large number of defects and cracks.
• Example 15 Dielectric data of dielectric films printed from precursor compositions containing bifunctionalized-silane ethylene glycol crosslinkers.
• Table 7 summarizes representative dielectric data (film roughness, capacitance (Cj) and breakdown voltage (BV)) of dielectric films printed from precursor compositions containing PVP and C 6 OAc or EGOAc, following procedures described in Examples 6, 8 and 13. Use of the ethylene glycol-based crosslinkers was shown to reduce film roughness and improve dielectric strength. Table 7
• Example 16 Insulating properties of dielectric films printed from precursor compositions containing thermally curable bifunctionalized-silane ethylene glycol crosslinkers.
• Example 17 Device performance of OFET fabricated with dielectric films printed from precursor compositions containing thermally curable bifunctionalized-silane ethylene glycol crosslinkers.
• FIGS. 15A and 15B are representative transfer and output plots for one of the printed PVP-EGOAc formulations (Entry 7, Table 7). All OTFT measurements described herein were carried out in air using a Keithly 6430 subfemtoammeter and a Keithly 2400 source meter, operated by a local Labview program and GPIB communication. Triaxial and/or coaxial shielding was incorporated into Signaton probe stations to minimize the noise level. A digital capacitance meter (Model 3000, GLK Instruments) and an HP4192A Impedance Analyzer were used for capacitance measurements.
• Figures 16A and 16B provide output plots for OFETs fabricated with the printed PVP-EGOAc formulation of Entry 7 in Table 5 as the dielectric component and, as the semiconductor component N,N'-bis(n-octyl)-(l ,7 and 1,6)- dicyanoperylene-3,4:9,10-bis(dicarboximide) (PDI-8CN 2 ) and 5,5'-di-(p- hexylphenyl)-2,2'-bithiophene (DH-PTTP), respectively.
• PDI-8CN 2 was prepared according to the procedures described in U.S. Patent Application Publication No. US 2005/0176970, the disclosure of which is incorporated by reference herein.
• Carrier mobility has been calculated in saturation.
• WAXRD wide angle x-ray diffraction
• Figure 18 provides a series of photographs of printed OFETs demonstrating mechanical flexibility.
• Example 18 Dielectric properties of dielectric films prepared from precursor compositions containing polymeric crosslinkers.
• Tables 9 and 10 summarize the properties of various dielectric films obtained from different polymer-crosslinkable copolymer precursor formulations having the formula:
• Table 9 shows that relatively high capacitance films can be fabricated both by spin-coating and printing various precursor formulations employing a thermally curable polymeric crosslink ⁇ ; formula: Table 9
• Table 10 shows that relatively high capacitance films can be fabricated both by spin-coating and printing various photochemically curable polymer- crosslinkable copolymer precursor formulations.
• crosslinked polymeric dielectric films of excellent quality were fabricated by spin-coating or printing various precursor formulations including a conventional polymer such as PVP, a thermally curable crosslinker such as EGOAc, and optioi (chemically curable polymeric crosslinker such as PVP x Cxn y .
• a conventional polymer such as PVP
• a thermally curable crosslinker such as EGOAc
• optioi chemically curable polymeric crosslinker
• PVP x Cxn y Optioi (chemically curable polymeric crosslinker

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