TW201348241A - Unconventional chemical doping of organic semiconducting materials - Google Patents

Abstract

Compositions comprising doped organic semiconductors with high charge carrier mobilities are formed which comprise at least one polycrystalline organic semiconductor comprising crystalline domains and grain boundaries at the interfaces, at least one neutral molecular dopant, wherein the dopant is dopant is not evenly distributed throughout the composition. Methods of making the compositions are also described.

Description

Non-practical chemical doping of organic semiconductor materials

The basic principle of doping in organic (small molecule and polymer) semiconductors is similar to the principle in inorganic semiconductors. In each case, it is necessary to introduce an "impurity", that is, a foreign atom or molecule that can transfer an electron to an electron conduction band or an energy state (for example, the lowest unoccupied molecular orbital (LUMO) in the case of an organic matter), Thereby forming an n-type doping, or a foreign atom or molecule that can migrate an electron from a hole conduction band/energy state (eg, the highest occupied molecular orbital (HOMO)) to generate a free hole, and thus form a p - type doping.

P-type and n-type doping in organic semiconductors and devices using this method have been demonstrated. See, for example, Pfeiffer et al, Org. Electron. 4, 89 (2003), Zhang et al, Phys. Rev. B , 81, 085201 (2010). In most cases, the doping process is typically a macroscopic phenomenon in which dopant molecules/elements are evenly distributed throughout the semiconductor, although alternative methods such as far-end doping have also been demonstrated. Zhao et al., Appl. Phys. Lett. 97, 123305 (2010). The materials used hitherto are mainly organic substances having relatively low charge carrier mobility.

However, when it is essentially an organic semiconductor with high charge carrier mobility, the introduction of molecular dopants may destroy molecular packing, a key property of thin films and electronic devices that achieve high carrier mobility, and This can result in reduced hole/electron mobility. As a result, conventional doping may be limited to organic materials having relatively low charge carrier mobility. There are self-assembled/stacked materials that are not very well performed (eg, solid amorphous structures).

Therefore, there is a need for a composition and a manufacturing method of a doped organic semiconductor having high charge carrier mobility. In addition, there is a need to dope a crystalline thin film transistor (TFT) with substantially no effect on the crystal packing of the film.

Embodiments described herein include compositions and compounds, as well as methods of manufacture, methods of use, inks and devices comprising the compositions and compounds.

An embodiment provides a method comprising: providing at least one liquid precursor composition formed by mixing at least the following components, (i) at least one hole or electron suitable for forming an organic polycrystalline phase Conducting an organic material, (ii) at least one neutral molecular dopant, and (iii) at least one solvent; forming at least one solid film from the liquid precursor composition, wherein the solid film comprises the at least one organic polycrystalline phase, It includes grain boundaries, and wherein the dopant is concentrated at the grain boundaries.

Another embodiment provides a composition comprising: at least one polycrystalline organic semiconductor comprising a crystalline region and a grain boundary at an interface of the crystalline region, and at least one neutral molecular dopant, wherein The dopant is enriched at the grain boundary at the interface of the crystalline region.

Another embodiment provides a method comprising: providing an ink formed by mixing at least: (i) at least one organic semiconductor suitable for forming a polycrystalline phase, (ii) at least one neutral molecular dopant a dopant, and (iii) at least one solvent; forming at least one solid film from the ink, wherein the solid film comprises the at least one organic semiconductor polycrystalline phase comprising a grain boundary, and wherein the dopant is not uniformly distributed The entire solid film.

At least one advantage of at least one embodiment is excellent electron or hole mobility.

Another advantage of at least one embodiment includes doping a crystalline semiconductor having a high charge carrier mobility in a single solution phase deposition.

However, another advantage of at least one embodiment includes the use of dopants having different structures and neutral charges to the crystalline material, thereby allowing the doping parameters and compositions to be flexible.

A further advantage of at least one embodiment is that for a small doping concentration, the resulting polycrystalline microstructure of the blend film appears to remain the same without any significant change.

Detailed description introduction

All references cited herein are hereby incorporated by reference in their entirety.

PCT/EP2011/056584 to Princeton University, filed on April 26, 2011, is hereby incorporated by reference in its entirety herein.

Compositions, compounds, derivatives and materials that produce organic semiconductors with high charge carrier mobility are known in the art. See, for example, PCT/EP2011/056584, filed April 26, 2011, Jones et al, Adv. Funct. Mater. , 2010, 20 , 2330-2337; Hamilton et al, Adv. Mater. , 2009 , 21, 1166-1171; Verlaak et al, Appl. Phys. Lett. (2003), 82(5), 745-747; and Smith et al, J. Mater. Chem. 2010, 20, 2562. Compositions, compounds, derivatives and materials of this type can be doped by methods such as remote doping and other methods. See, for example, Zhao et al., Appl. Phys. Lett. , 2010, 97, 123305. See also, Chen et al, J. Phys. Chem. B, 2004, 108, 17329-17336. The compositions, compounds, derivatives and/or materials of the prior art do not teach or suggest embodiments of the present invention.

combination

At least one embodiment provides at least one polycrystalline organic semiconductor comprising a crystalline region and a grain boundary at an interface of the crystalline region, and at least one neutral molecular dopant, wherein the dopant is located at an interface of the crystalline region Enrichment. Another embodiment provides at least one polycrystalline organic semiconductor comprising a crystalline region and a grain boundary at an interface of the crystalline region, and at least one neutral molecular dopant, wherein the dopant is not uniformly distributed throughout the solid film . Reflected The composition may further comprise a non-conductive or semi-conductive material of at least one amorphous polymer.

Polycrystalline organic semiconductor material

In some embodiments, the polycrystalline organic semiconductor material can include a crystalline or semi-crystalline hole transport material or a crystalline or semi-crystalline electron transport material.

In one embodiment, the at least one polycrystalline organic semiconductor comprises a hole transport material selected from the group consisting of randomly substituted oligomeric thick benzene represented by the formula (I).

Wherein R _{1 to} R _{10 are} independently H, alkyl, fluoroalkyl, alkoxy, aryl, heteroaryl, halogen, trialkyldecylethynyl, each optionally substituted by one or more halogens Substituted with a cyano group, an alkyl group or an alkoxy group, and n is from 0 to 10.

In a preferred embodiment, the at least one polycrystalline organic semiconductor comprises a hole transport material represented by the chemical formula (II): Wherein in each case R' is independently selected from C ₁ -C ₁₀ alkyl, aryl or heteroaryl, each optionally being one or more halogen, cyano, alkyl or alkoxy Replaced by the regiment.

In another embodiment, the at least one polycrystalline organic semiconductor comprises a hole transport material selected from the group consisting of randomly substituted oligoacene benzene represented by the formula (III): Wherein the two X moieties are independently O, S, Se, NH; and R _{1 -} R _{8 are} independently H, alkyl, fluoroalkyl, alkoxy, aryl, heteroaryl, tri Alkylmercaptoethynyl, halogen, arylethynyl, heteroarylethynyl; and n is 0 to 10. In a preferred embodiment, the at least one polycrystalline organic semiconductor comprises a hole transport material represented by the chemical formula (IV): Wherein in each case R' is independently selected from C ₁ -C ₁₀ alkyl, aryl or heteroaryl, each optionally being one or more halogen, cyano, alkyl, or alkoxy Replacement of the group.

In another embodiment, the at least one polycrystalline organic semiconductor comprises a hole transport material selected from the group consisting of randomly substituted oligoacene benzene represented by the formula (V): Wherein in each case X is independently O, S, Se, NH; R _{1 -} R _{8 are} independently H, alkyl, fluoroalkyl, alkoxy, aryl, heteroaryl, trialkyl fluorene Ethyl ethynyl, halogen, arylethynyl, heteroarylethynyl; and n and n' are independently from 0 to 5.

In a preferred embodiment, the at least one polycrystalline organic semiconductor comprises a hole transporting material selected from the group consisting of randomly substituted oligomeric fused benzene fused thienothiophenes represented by the formula (VI): Wherein R ₁ and R _{2 are} independently selected from the group consisting of H, alkyl, fluoroalkyl, aryl, heteroaryl, trialkyldecylethynyl, arylethynyl and heteroarylethynyl; and n and n' Independently 0, 1 or 2.

In another embodiment, the at least one polycrystalline organic semiconductor comprises an electron transporting material comprising randomly substituted aryl or heteroaryl groups. Optionally substituted aryl or heteroaryl groups are known in the art as electron transporting materials and can be embodied, for example, by reference.

In another embodiment, the at least one polycrystalline organic semiconductor comprises an electron transport material selected from the group consisting of indenyl imine represented by the formula (VII): Wherein R ₁ and R ₂ are independently selected from the group consisting of a straight chain, a branched chain, or a cyclic alkyl group, an aryl group, a heteroaryl group, an alkyl-aryl group, or an alkyl-heteroaryl group C ₁ - a C ₃₀ organic group (optionally substituted with one or more halogen, cyano, alkyl or alkoxy groups). See, for example, Nature Mater. , 2009, 8, 952.

In another embodiment, the at least one polycrystalline organic semiconductor comprises an electron transport material selected from the group consisting of naphthalene diimine represented by the formula (VIII): Wherein hAr is heteroaryl; R ¹ and R ^{1 '} are each independently selected from a straight chain, branched, or cyclic alkyl, aryl, heteroaryl, alkyl-aryl, or alkyl- a C ₁ -C ₃₀ organic group of an arylalkyl group (optionally substituted with one or more halogen, cyano, alkyl or alkoxy groups); R ² , R ³ and R ⁴ independently An organic group selected from the group consisting of hydrogen, halogen, or C ₁ -C ₃₀ is independently selected from the group consisting of a cyano group, a linear, branched, or cyclic alkyl group, a fluoroalkyl group, an aryl group, a heteroaryl group, an alkyl group. An aryl, fluorenyl-heteroaryl and alkyl-heteroaryl group (optionally substituted with one or more fluorine, cyano, alkyl, alkoxy groups).

Further examples of crystalline or semi-crystalline hole transport materials embodied herein include pentacene or substituted pentacene derivatives such as TIPS pentacene (6,13-bis(triisopropyl-decylacetylene) A pentacene), a rubrene or a rubrene derivative, a metal phthalocyanine such as copper phthalocyanine or zinc phthalocyanine, or a regioregular alkyl polythiophene, the structure of which is shown below.

Amorphous polymer organic material

In one embodiment, the composition further comprises at least one amorphous polymer organic semiconductor or a non-conductive material. The amorphous polymer organic semiconductor material can be a known compound, such as those incorporated by reference. In another embodiment, the composition does not comprise Including amorphous polymer organic materials. In another embodiment, the amorphous polymer organic semiconductor or non-conductive material is a polymeric binder.

In one embodiment, the at least one amorphous polymeric organic material comprises a polymer, the backbone or polymer backbone of the polymer comprising randomly substituted arylamine units. The amorphous polymer organic material may be selected, for example, from a polymer whose side chain includes a triarylamine or carbazole unit.

In one embodiment, the at least one amorphous polymer organic material comprises a material of a subunit represented by the chemical formula (IX): Wherein R _{a is,} in each case, independently selected from C ₁ -C ₁₀ alkyl, optionally substituted aryl or heteroaryl, k is an integer from 0 to 5, and n can be, for example, from 10 to 1000 as a statistical average known to those skilled in the art of polymer chemistry. The number average molecular weight may be, for example, 2,500 g/mol to 25,000 g/mol, and the value of n may be determined from the number average molecular weight and molecular weight of the repeating unit.

In some embodiments, the at least one amorphous polymer organic material may further include at least one selected from the group consisting of randomly substituted poly(styrene), poly(α-methylstyrene), and poly(vinylbiphenyl). , or an amorphous polymer in poly(methyl methacrylate).

In other embodiments, the amorphous polymer organic material is in A copolymer, a block polymer, or a mixture of two or more polymers. In other embodiments, the polymer is linear or branched and includes star polymers, comb polymers, brush polymers, dendrimers, and dendrimers.

Dopant

The dopants embodied herein may be p-type dopants or n-type dopants. In one embodiment, the dopant comprises a transition metal p-type dopant. In another embodiment, the dopant comprises a metallic n-type dopant. The dopants embodied herein may include known compounds. In one embodiment, the dopant is characterized by selective separation (eg, dopant molecules tend to separate at specific locations in the composition, such as grain boundaries within the film).

Embodiments of the invention contemplate a wide range of dopant materials. In one embodiment, the dopant is a neutral molecular dopant, which is said to be not a zwitterionic or ionic molecule.

In many embodiments, the dopant is a p-type dopant. In one embodiment, the p-type dopant is a strong oxidant, such as the known dopant tetrafluoro-TCNQ (tetracyano-p-benzoquinodimethane).

In some embodiments, the material of the p-type dopant is a transition metal complex, such as those disclosed in WO 2008/061517, for example, including structures 1 through 6 as shown below: Wherein M is a transition metal, preferably Cr, Mo or W, and R _{1 -} R _{6 are} independently selected from H, substituted or unsubstituted C ₁ -C ₁₀ alkyl, C ₁ -C ₁₀ -thienyl , perfluorinated alkyl, phenyl, tolyl, N,N-dimethylaminophenyl, anisyl, benzhydryl, CN or COOR ₇ wherein R ₇ is C ₁ -C ₅ -alkyl X system S, Se, NR ₁₀ wherein R ₁₀ is alkyl, perfluoroalkyl, cycloalkyl, aryl, heteroaryl, ethenyl or CN.

In one embodiment, the transition metal p-type dopant comprises a complex represented by formula (X): Wherein M is Cr, Mo or W, and R ₁ -R _{6 are} independently selected from C ₁ -C ₃₀ fluorinated alkyl, cyano, or optionally substituted aryl, heteroaryl. This embodiment includes a preferred p-type dopant Mo(tfd) ₃ having the structure shown below:

In one embodiment, the at least one dopant is a known n-type dopant. In one embodiment, a known n-type dopant allows the conductivity and/or electron mobility of the composition to be measured, the composition comprising at least one polycrystalline organic comprising a crystalline region and a grain boundary at the interface The semiconductor, and at least one dopant with a very large increase, is preferably increased by at least a factor of two, or preferably by at least a factor of 10.

In another embodiment, the ionization energy of the n-type dopant, as determined using photoelectron spectroscopy, is less than about 3.5 eV.

The dopant can be, for example, an n-type dopant including an alkali metal, a transition metal, a lanthanide metal or a lanthanide metal.

In another embodiment, the dopant comprises at least one transition metal sandwich complex represented by the formula (XI-XIII):

Wherein M ^vii is manganese or ruthenium; M ^viii is iron, ruthenium or osmium; M ^ix is ruthenium or osmium; each R ^cp and R ^{bz are} independently selected from hydrogen or optionally substituted C ₁ -C ₁₂ alkyl a group or a C ₁ -C ₁₂ phenyl group; x and x' are each independently selected from an integer from 1 to 5; and y and y" are each independently selected from an integer from 1 to 5, and y' is from 1 An integer of -6.

In another embodiment, the dopant comprises at least one transition metal sandwich complex represented by the chemical formula (XIV-XVI): Wherein M ^vii is manganese or ruthenium; M ^viii is iron, ruthenium or osmium; M ^ix is ruthenium or osmium; each R ^cp , R ^bz and R ^{d are} independently selected from hydrogen or optionally substituted C ₁ -C _{a 12} alkyl group or a C ₁ -C ₁₂ phenyl group; x and x' are each independently selected from an integer from 1 to 5; and y and y" are each independently selected from an integer from 1 to 5, and y' An integer from 1-6.

In another embodiment, the at least one dopant comprises a dopant as disclosed in J. Am. Chem. Soc. , 2010, 132, 8852, such as N-DMBI represented by chemical formula (XVII) derivative: Wherein R ₁ , R _{2 are} independently selected from alkyl, aryl or heteroaryl.

Another effect of the unique doping of this embodiment may be to reduce threshold voltage fluctuations between different thin film transistors. Thus, thin film transistors fabricated in a similar manner can provide more consistent electrical characteristics by reducing threshold voltage fluctuations. In some embodiments, it is believed that this reduced threshold voltage can be seen, for example, an improved performance of a 7-stage ring oscillator. In one embodiment, the fluctuation between the two transistors fabricated in the same manner is about ± 5%, ± 4%, ± 3%, ± 2%, ± 1%, ± 0.1%, ± 0.01%. Within ±0.001% or ±0.0001%.

The dopant can be present in the composition at an effective concentration to cause a desired change in the electrical properties of the material or device in which the material is incorporated. In one embodiment, the dopant is present at a concentration of from about 0.001% to about 2.0% by weight of the composition. In another embodiment, the dopant is present at a concentration of from about 0.0001% to about 2.0% by weight of the composition. In another embodiment, the dopant is present in an amount of less than 2.0% by weight of the composition.

In one embodiment, the dopant is at least one p-type dopant, and the semiconductor or composition thereof has a hole mobility of at least 0.2 cm ² /V. s, at least 0.5 cm ² /V. s, or at least 1.0 cm ² /V. s. In another embodiment, the dopant is an n-type dopant, and the semiconductor or composition has an electron mobility of at least 0.2 cm ² /V. s, or at least 0.5 cm ² /V. s, or at least 1.0 cm ² /V. s.

In another embodiment, the concentration of the dopant is such that the discrete device parameters are reduced by at least 20%, or at least 30%, or at least 40%, or at least 50%, or at least 50% or more. . In another embodiment, the concentration of the dopant is such that the threshold voltage of the composition or device is reduced by at least 50%, or at least 60% or at least 70%, compared to the lack of dopants. A composition or device.

In some embodiments, the at least one dopant comprises two or more dopants. In some embodiments, the dopants present in the composition are 1, 2, 3, 4 or 5 dopants. The dopants can be any of the dopants disclosed herein, or in addition to those disclosed herein, in addition to additional combinations of dopants known in the art.

Grain boundaries

In one embodiment, the composition includes at least one polycrystalline organic semiconductor comprising a crystalline region and a grain boundary at the interface. In another embodiment, the composition may further comprise an amorphous polymer organic compound. The grain boundary may be an interface between two crystal grains or two crystal regions, or may be an interface between the crystal region and an amorphous polymer organic compound.

Crystallized area

The crystalline region in this embodiment includes an organic semiconductor material. In some embodiments, the crystalline region is substantially free of components other than the organic semiconductor material. In other embodiments, the crystalline region is 95%, 98%, 99%, 99.5%, 99.9%, or 99.99% free of components other than the organic semiconductor material. In some embodiments, a component other than the organic semiconductor material, for example, a dopant or an amorphous polymer organic compound, may be present in the crystalline region. In one embodiment, when the dopant is present in the crystalline region, it is present at a concentration that is lower than the concentration of the dopant at the grain boundary.

In another embodiment, the crystalline regions can include aligned polycrystalline regions.

Method of manufacturing a film

A method of manufacturing a film for an OTFT is enumerated and conceived as follows. In at least one embodiment, a method for forming at least one solid film is provided, comprising: providing at least one liquid precursor composition formed by mixing at least the following components: (i) at least a hole or electron conducting organic material suitable for forming an organic polycrystalline phase, (ii) at least one neutral molecular dopant, and (iii) at least one solvent; forming at least one solid film from the liquid precursor composition, wherein The solid film includes the at least one organic polycrystalline phase comprising a grain boundary, and wherein the dopant is concentrated at the grain boundary. In some embodiments, the liquid precursor further comprises at least one hole or electron conducting organic material suitable for forming an organic amorphous phase.

In another embodiment, the method comprises: providing an ink formed by at least mixing the following components: (i) at least one organic semiconductor suitable for forming a polycrystalline phase, (ii) at least one neutral molecular dopant a dopant, and (iii) at least one solvent; forming at least one solid film from the ink, wherein the solid film comprises the at least one organic semiconductor polycrystalline phase comprising a grain boundary, and wherein the dopant is not uniformly distributed The entire solid film. The ink in the present embodiment can be formed by additionally mixing at least one organic material which is a polymer binder of the organic semiconductor polycrystalline phase.

In one embodiment, the liquid precursor is formed by combining, suspending, or otherwise combining at least one polycrystalline organic semiconductor material with at least one dopant in one or more organic solvents. Optionally, an amorphous polymer organic compound, or a polymeric binder, which may be a semiconducting material or a non-conductive material, may also be incorporated into the liquid precursor. It is contemplated that different materials, ie (i) small molecule semiconductors, (ii) amorphous polymer organic compounds or polymer binders, and/or (iii) dopant molecules can be prepared as separate solutions, which are later The stages are mixed to form the final blend solution. There are generally more than one solvent involved: one is an optional polymer binder and a small molecule semiconductor, and the other is a dopant. It is possible to use three different solvents for each optional blending component. Additional compounds can be incorporated into the liquid precursor.

In one embodiment, the deposition is carried out by known techniques, such as a dissolution process, in which the material forming the film, such as a polymer, is dissolved. The liquid precursor is formed in a usual organic solvent and then carried out by spin coating or ink jet printing of such a solution to a substrate.

In one embodiment, the solid film is formed by evaporating the at least one organic solvent from the deposited liquid precursor. The optional additional liquid compound, if present in the liquid precursor, may be evaporated or solidified to form a solid film. The liquid precursor is typically deposited on a solid surface, such as a substrate. The substrate may already contain other coatings because the solid substrate can ultimately take a variety of physical forms. Forms include, for example, for devices and field effect transistors, including bottom gate top contact type and bottom contact top gate field type field effect transistors. These may be fabricated by standard techniques for synthesizing organic electronic devices well known to those of ordinary skill in the art of organic electronic devices, as shown in various prior art portions referred to herein, and incorporated by reference.

Ink is also considered in the present embodiment. In some embodiments, the ink can include a liquid precursor. In another embodiment, the ink is used in a method comprising providing an ink formed by at least mixing the following components: (i) at least one organic semiconductor suitable for forming a polycrystalline phase, (ii) Optionally, at least one organic material, which is a polymer binder of an organic semiconductor polycrystalline phase, (iii) at least one molecular dopant, and (iv) at least one solvent; forming at least one solid film from the ink Wherein the solid film comprises the at least one organic semiconductor polycrystalline phase comprising grain boundaries, and wherein the dopant is not uniformly distributed throughout the solid film.

In one embodiment, the organic semiconductor is a polycrystalline organic semiconductor material as disclosed herein. In one embodiment, the at least one organic material (a polymer binder of the organic semiconductor polycrystalline phase) is a hole or an electron conducting organic material suitable for forming an organic amorphous phase, or it is an amorphous polymer non- A conductive material, or it is an amorphous polymer organic semiconductor. In an embodiment, the dopant comprises a dopant as embodied herein. In another embodiment, the method comprises the at least one organic material which is a polymeric binder of the organic semiconductor polycrystalline phase.

Working example Example 1. Production of liquid precursors and solid films

To an amorphous p-type polymer poly(triarylamine) containing 2,8-difluoro-5,11-bis(triethyldecylethynyl)dithiophene (diF-TESADT) and in tetrahydronaphthalene An organic blend of (PTAA) polymer, adding a certain amount of a known p-type dopant organometallic complex Mo tri-[1,2-bis(trifluoromethyl) dissolved in chlorobenzene Ethane-1,2-dithiolene] (MoTDT). The doping concentration is adjusted by controlling the concentration of solid components in the dopant solution added to the neat semiconductor solution. The solution was deposited onto a substrate and a composite film was formed by evaporating the solvent.

Example 2. Making of a ring oscillator based on a bottom gate contact type transistor Make

An integrated circuit using a polyethylene phenol (PVPh) as a gate dielectric using a bottom gate contact type device architecture and a number of discrete transistors are shown in Figure 5, using polyvinylpyrrolidone (PVP, That is, dielectric) a general-purpose transistor to construct a reverse and ring oscillator circuit. SAM here refers to self-assembled monolayer pentafluorobenzenethiol (PFBT) used as a contact work function modifier to improve hole injection from the gold (Au) electrode to the hole transporting small molecule HOMO levels.

The detailed production process is described elsewhere (see, for example, GH Gelinck et al., Nature Mater. 3 , 106 (2004)). Briefly, the circuit structure consists of a gold electrode, a connector, and a 300 nm polyvinylpyrrolidone (PVP) layer patterned to form vertical interconnects (vias). The source and drain electrodes are treated with pentafluorobenzenethiol solution (PFBT) prior to semiconductor deposition to improve charge injection and channel material crystallinity (see, for example, DJ Gundlach et al, Nature Mater. 7, 216 (2008)). The semiconductor blending process was carried out by spin coating followed by annealing at 100 ° C for 150 sec in N ₂ . For best performance, the integrated circuit was further annealed in vacuum (10 ^-5 mbar) at 100 ° C for 30 min. Electrical measurements were carried out in the dark at room temperature in vacuo. The phase delay time (τ _d ) of each ring oscillator is calculated from the measured oscillation frequency (f _osc ) using τ _d =(1/2nf _osc ), where n is the number of inversion phases. The charge carrier mobility was calculated from the transfer characteristics using a geometric capacitance (C _i ) of the PVP layer of 10 nF/cm ² as determined by impedance measurement.

Example 3. Fabrication of a top gate bottom contact transistor

A top gate bottom contact transistor was fabricated on a glass substrate by evaporation of a gold source-drain electrode (S-D) and using self-assembled monolayer pentafluorobenzene mercaptan (PFBT) as a work function modifier. The length and width of the transistor channel vary between 20 μm and 100 μm and between 0.5 mm and 2.0 mm, respectively. The semiconductor consists of a blend of diF-TESADT and PTAA with or without dopant molecules. The gate dielectric consists of a 900 nm thick fluoropolymer CYTOP layer which is also spin coated directly onto the blended semiconductor and annealed at 100 ° C for 5 minutes in a nitrogen atmosphere. The gate electrode is then thermally evaporated using a shadow mask directly on the CYTOP layer.

Example 4 device form

The morphology of the formed composite membrane was investigated using a polarizing microscope (PLM). No signs of disruption of the crystalline regions in any of the composite membranes were observed. Electrical measurements of the doped film of the transistor structure showed that the electrical properties of the device varied significantly during doping. For example, when a film is doped with a different amount of MoTDT, it is found that the threshold voltage of the transistor moves toward a positive gate voltage (i.e., near zero volt gate bias), which is a desirable characteristic. The latter observation is most likely to indicate a decrease in the trap density of the semiconductor/dielectric interface as the doping concentration increases.

Example 5. Determining the movement of the Fermi level

Next, the measurement of the shift of the Fermi level (EF) of the semiconductor blend film with increasing doping concentration was investigated. It is done using an ultraviolet photoelectron spectroscopy (UPS) method. The results obtained are reproduced in Figure 1 and do not exhibit any strong signal of conventional doping, i.e., the Fermi level shifts as the MoTDT concentration increases. These results are further quantified as listed in Table 1.

Example 6. Obtaining the measured electrical parameters of different concentrations of MoTDT doped diF-TESADT: PTAA blended crystals

Next, electrical parameters of diF-TESADT:PTAA blended crystals with different MoTDT doping concentrations (1 wt%, 0.5 wt%, 0.1 wt%, and 0 wt%) were obtained. These parameters are obtained assuming a gate geometry capacitance of 1.2 nF/cm ² . Where W and L are the width and length of the channel, respectively, and μ _lin and μ _sat represent the linear and saturated mobility found by the same device. As summarized in Table 2, it was observed that as the MoTDT concentration increased, even up to 1 wt% of the doping concentration, the threshold voltage (VT) of the blended transistor decreased while maintaining relatively high hole mobility. These results are further illustrated in Figure 2.

Example 7. Effect of doping on trap deactivation temperature

In order to study the effect of doping on trap deactivation, measurements with temperature were measured and the activation energy of the hole transport was determined. The results are shown in Figure 3 and show that the hole transport mechanisms in the doped and undoped devices appear to be different. Specifically, the hole transport of the undoped device exhibited two different modes, one observed at low temperatures (T < 120 K) and one observed at higher temperatures (T > 120 K). In the case of a doped sample, a single activation energy is exhibited over the entire temperature range and the sample exhibits high mobility throughout the temperature range studied.

Example 8. Effect of a device comprising a blend of diF-TES ADT:PTAA with MoTDT

To further investigate the effect of MoTDT molecular doping on the diF-TES ADT:PTAA blend, a 7-stage ring oscillator based on bottom gate contact type OTFTs as described in the previous examples was fabricated. In this case, the blended semiconductor is directly spin coated onto the circuit substrate with and without the dopant, and then in an inert atmosphere (nitrogen atmosphere). Electrical characterization. A representative result is shown in Figure 4, where for the doped and undoped film-based circuits, the oscillation frequency of the 7-stage ring oscillator is plotted as a function of the applied voltage.

Figure 1. Measurement of UV photoelectron spectroscopy of doped and undoped blended films (MoTDT diF-TES ADT: PTAA). No change in the energetics of the doped MoTDT film was observed.

Figure 2. shows the effect of a diF-TES ADT:PTAA blend film doped with MoTDT.

Figure 3. Arrhenius plot showing saturated hole mobility measured based on organic TFT (OTFT) doped and undoped blends. This suggests that the hole transport mechanisms in the doped and undoped devices appear to be different.

Figure 4. shows the oscillation frequency as a function of applied voltage, measured from a seven-stage ring oscillator based on doped and undoped diF-TES ADT:PTAA blended semiconductors.

Figure 5. shows an example diagram of a transistor for constructing a reverse and ring oscillator circuit.

Claims (65)

A method comprising: providing at least one liquid precursor composition formed by mixing at least: (i) at least one hole or electron conducting organic material suitable for forming an organic polycrystalline phase, ( Ii) at least one neutral molecular dopant, and (iii) at least one solvent; forming at least one solid film from the liquid precursor composition, wherein the solid film comprises the at least one organic polycrystalline phase comprising a grain boundary, And wherein the dopant is concentrated at the grain boundary. The method of claim 1, wherein the liquid precursor further comprises at least one hole or electron conducting organic material suitable for forming an organic amorphous phase. The method of claim 1, wherein the dopant is a p-type dopant. The method of claim 1, wherein the dopant is an organometallic complex. The method of claim 1, wherein the dopant comprises a complex represented by the chemical formula (X): Wherein M is Cr, Mo or W, and R ₁ -R _{6 are} independently selected from C ₁ -C ₃₀ fluorinated alkyl, cyano, or optionally substituted aryl, heteroaryl. The method of claim 1, wherein the dopant is an n-type dopant. The method of claim 1, wherein the dopant is an n-type dopant comprising an alkali metal, a transition metal, a lanthanide metal or a lanthanide metal. The method of claim 1, wherein the at least one hole or electron-conducting organic material suitable for forming an organic crystalline phase comprises a hole transporting material. The method of claim 1, wherein the at least one hole or electron-conducting organic material suitable for forming an organic crystalline phase comprises a hole transporting material comprising two or more conjugated One or more organic compounds of an aryl or heteroaryl ring. The method of claim 1, wherein the at least one hole or electron-conducting organic material suitable for forming the at least one organic polycrystalline phase comprises a hole transporting material comprising two or more A conjugated substituted aryl or heteroaryl ring and one or more organic compounds of one or more thiol moieties. The method of claim 1, wherein the at least one hole or electron-conducting organic material suitable for forming the organic polycrystalline phase comprises a hole transporting material represented by the formula (II) or (IV): Wherein R 'at each occurrence is independently selected from C ₁ -C ₁₀ alkyl, optionally substituted aryl or heteroaryl group. The method of claim 2, wherein the at least one hole or electron-conducting organic material suitable for forming an organic amorphous phase comprises a randomly substituted poly(arylamine), poly(arylamine) polymer The backbone contains an aryl moiety. The method of claim 2, wherein the at least one hole or electron-conducting organic material suitable for forming an organic amorphous phase comprises a randomly substituted poly(triarylamine). The method of claim 2, wherein the at least one hole or electron-conducting organic material suitable for forming an amorphous phase comprises a copolymer comprising at least one randomly substituted poly(triarylamine). The method of claim 2, wherein the at least one hole or electron-conducting organic material suitable for forming an organic amorphous phase comprises a compound represented by the formula (IX): Wherein R _a is independently selected from C ₁ -C ₁₀ alkyl, optionally substituted aryl or heteroaryl in each case; k is an integer from 0 to 5; n is 10 to 1000. The method of claim 2, wherein the at least one hole or electron-conducting organic material suitable for forming an organic crystalline phase has a molecular weight of about 1,000 g/mole or less, and is suitable for forming an organic amorphous phase. The at least one hole or electron conducting organic material has a number average molecular weight of at least 1000. The method of claim 2, wherein when the solvent is removed, the dopant is present in an amount of from 0.001% by weight to 2.0% by weight of the composition, the composition being suitable for forming an organic crystalline phase. At least one hole or electron conducting organic material, the at least one hole or electron conducting organic material suitable for forming an organic amorphous phase and the at least one dopant. The method of claim 1, wherein the liquid precursor composition is formed on a substrate, wherein the forming step comprises an inkjet coating or spin coating step. The method of claim 1, wherein the at least one solvent is an organic solvent. The method of claim 1, wherein the at least one solvent is selected from the group consisting of tetrahydronaphthalene, chlorobenzene, dichlorobenzene, chloroform, and THF. A composition comprising: At least one polycrystalline organic semiconductor comprising a crystalline region and a grain boundary at an interface of the crystalline region, and at least one neutral molecular dopant, wherein the dopant is enriched at a grain boundary at an interface of the crystalline regions . The composition of claim 21, wherein the polycrystalline organic semiconductor is a small molecule having a molecular mass of less than 3000 Da. The composition of claim 21, additionally comprising an amorphous polymer organic semiconductor. The composition of claim 21, further comprising an amorphous polymer non-conductive material. The composition of claim 21, wherein the dopant is present in a concentration from 0.001% to 2.0% by weight of the composition. The composition of claim 21, wherein the organic semiconductor has at least 0.5 cm ² /V. The hole mobility of s, and the at least one dopant is a p-type dopant. The composition of claim 21, wherein the at least one dopant comprises a p-type dopant of a transition metal. The composition of claim 21, wherein the at least one dopant comprises a complex represented by the formula (X): Wherein M is Cr, Mo or W, and R ₁ -R ₄ are independently selected from C ₁ -C ₃₀ fluorinated alkyl, cyano, or optionally substituted aryl or heteroaryl. The composition of claim 21, wherein the organic semiconductor has at least 0.5 cm ² /V. The electron mobility of s, and the at least one dopant is an n-type dopant. The composition of claim 21, wherein the at least one dopant comprises an N-DMBI derivative represented by the chemical formula (XVII): Wherein R ₁ , R ₂ are independently selected from alkyl, aryl or heteroaryl. The composition of claim 21, wherein the at least one dopant comprises a transition metal sandwich complex represented by the chemical formula (XI-XIII): Wherein M ^vii is manganese or ruthenium; M ^viii is iron, ruthenium or osmium; M ^ix is ruthenium or osmium; each R ^cp and R ^{bz are} independently selected from hydrogen or optionally substituted C ₁ -C ₁₂ alkyl a group or a C ₁ -C ₁₂ phenyl group; x and x' are each independently selected from an integer from 1 to 5; and y and y" are each independently selected from an integer from 1 to 5, and y' is from 1 An integer of -6. The composition of claim 21, wherein the at least one dopant comprises a transition metal sandwich complex represented by the chemical formula (XIV-XVI): Wherein M ^vii is manganese or ruthenium; M ^viii is iron, ruthenium or osmium; M ^ix is ruthenium or osmium; each R ^cp , R ^bz and R ^{d are} independently selected from hydrogen or optionally substituted C ₁ -C _{a 12} alkyl group or a C ₁ -C ₁₂ phenyl group; x and x' are each independently selected from an integer from 1 to 5; and y and y" are each independently selected from an integer from 1 to 5, and y' An integer from 1-6. The composition of claim 21, wherein the at least one polycrystalline organic semiconductor comprises a hole transporting material comprising two or more conjugated aryl or heteroaryl rings. One or more organic compounds. The composition of claim 21, wherein the at least one polycrystalline organic semiconductor comprises a hole transport material selected from the group consisting of randomly substituted oligomeric thick benzene represented by the formula (I): Wherein R _{1 to} R _{10 are} independently H, alkyl, fluoroalkyl, alkoxy, aryl, heteroaryl, halogen, trialkyldecylethynyl, and n is 0 to 10. The composition of claim 21, wherein the at least one polycrystalline organic semiconductor comprises a hole transport material represented by the chemical formula (II): Wherein R 'at each occurrence is independently selected from C ₁ -C ₁₀ alkyl, optionally substituted aryl or heteroaryl group. The composition of claim 21, wherein the at least one polycrystalline organic semiconductor comprises a hole transporting material selected from the group consisting of randomly substituted oligo-rich benzene represented by the formula (III): Wherein X is independently O, S, Se, NH; R _{1 -} R _{8 are} independently H, alkyl, fluoroalkyl, alkoxy, aryl, heteroaryl, trialkyldecylethynyl, halogen , arylethynyl, heteroarylethynyl; and n is 0 to 10. The composition of claim 21, wherein the at least one polycrystalline organic semiconductor comprises a hole transport material represented by the chemical formula (IV): Wherein R 'at each occurrence is independently selected from C ₁ -C ₁₀ alkyl, optionally substituted aryl or heteroaryl group. The composition of claim 21, wherein the at least one polycrystalline organic semiconductor comprises a hole transporting material selected from the group consisting of randomly substituted oligo-rich benzene represented by the formula (V): Wherein X is independently O, S, Se, NH; R _{1 -} R _{8 are} independently H, alkyl, fluoroalkyl, alkoxy, aryl, heteroaryl, trialkyldecylethynyl, halogen An arylethynyl group, a heteroarylethynyl group; and n and n' are independently from 0 to 5. The composition of claim 21, wherein the at least one polycrystalline organic semiconductor comprises a hole transporting material selected from the group consisting of randomly substituted oligomeric fused benzene fused thienothiophenes represented by the formula VI): Wherein R ₁ and R _{2 are} independently selected from the group consisting of H, alkyl, fluoroalkyl, aryl, heteroaryl, trialkyldecylethynyl, arylethynyl and heteroarylethynyl; and n and n' Independently 0, 1 or 2. The composition of claim 21, wherein the at least one polycrystalline organic semiconductor comprises an electron transporting material comprising an optionally substituted aryl group. The composition of claim 21, wherein the at least one polycrystalline organic semiconductor comprises an electron transporting material selected from the group consisting of quinone diimine represented by the formula (VII): Wherein R ₁ and R ₂ are independently selected from the group consisting of a straight chain, a branched chain, or a cyclic alkyl group, an aryl group, a heteroaryl group, an alkyl-aryl group, or an alkyl-heteroaryl group C ₁ - A C ₃₀ organic group optionally substituted with one or more halogen, cyano, alkyl or alkoxy groups. The composition of claim 21, wherein the at least one polycrystalline organic semiconductor comprises an electron transporting material selected from the group consisting of naphthalene diimine represented by the formula (VIII): Wherein hAr is heteroaryl; R ¹ and R ^{1 '} are each independently selected from a straight chain, branched, or cyclic alkyl, aryl, heteroaryl, alkyl-aryl, or alkyl- a C ₁ -C ₃₀ organic group of a heteroaryl group optionally substituted with one or more halogen, cyano, alkyl or alkoxy groups; R ² , R ³ and R ^{4 are} independently selected from hydrogen, Halogen, or a C ₁ -C ₃₀ organic group, independently selected from cyano, straight-chain, branched, or cyclic alkyl, fluoroalkyl, aryl, heteroaryl, alkane A aryl-aryl, a fluorenyl-heteroaryl group and an alkyl-heteroaryl group (optionally substituted with one or more fluorine, cyano, alkyl, alkoxy groups). The composition of claim 21, further comprising an amorphous polymer organic semiconductor selected from the group consisting of polymers The backbone includes randomly substituted arylamine units. The composition of claim 21, further comprising an amorphous polymer organic semiconductor selected from the group consisting of a unit having a triarylamine or a carbazole. The composition of claim 21, further comprising an amorphous polymer organic semiconductor having the subunit represented by the formula (IX): Wherein R _a is independently selected in each case from C ₁ -C ₁₀ alkyl, optionally substituted aryl or heteroaryl; k is an integer from 0 to 5; n is from 10 to 1000. The composition of claim 21, further comprising at least one selected from the group consisting of randomly substituted poly(styrene), poly(α-methylstyrene) and poly(vinylbiphenyl), or poly(A) Amorphous polymer in methyl acrylate). An ink comprising a composition as claimed in claim 21. An ink comprising a composition as claimed in claim 21, wherein the ink is suitable for spin coating or ink jet printing. A device comprising a composition as claimed in claim 21. A device comprising a field effect transistor comprising a composition as claimed in claim 21 of the patent application. A field effect transistor comprising a composition as claimed in claim 21 wherein the threshold voltage is reduced by at least 50% compared to the same composition lacking the dopant. A method comprising: providing an ink formed by at least mixing: (i) at least one organic semiconductor suitable for forming a polycrystalline phase, (ii) at least one neutral molecular dopant, and (iii) At least one solvent; forming at least one solid film from the ink, wherein the solid film comprises the at least one organic semiconductor polycrystalline phase comprising grain boundaries, and wherein the dopant is not uniformly distributed throughout the solid film. The method of claim 52, wherein the ink is formed by additionally mixing at least one organic material which is a polymer binder of the organic semiconductor polycrystalline phase. The method of claim 52, wherein the dopant is an organometallic complex. The method of claim 52, wherein the dopant is a p-type dopant comprising a transition metal. The method of claim 52, wherein the dopant comprises a complex represented by the chemical formula (X): Wherein M is Cr, Mo or W, and R ₁ -R ₄ are independently selected from C ₁ -C ₃₀ fluorinated alkyl, cyano, or optionally substituted aryl or heteroaryl. The method of claim 52, wherein the dopant is an n-type dopant. The method of claim 52, wherein the dopant is an n-type dopant comprising an alkali metal, a transition metal, a lanthanide metal or a lanthanide metal. The method of claim 52, wherein the at least one hole or electron-conducting organic material suitable for forming an organic crystalline phase comprises a hole transporting material. The method of claim 52, wherein the at least one hole or electron-conducting organic material suitable for forming an organic crystalline phase comprises a hole transporting material comprising two or more conjugated One or more organic compounds of an aryl or heteroaryl ring. The method of claim 52, wherein the at least one hole or electron conducting organic material suitable for forming the at least one organic polycrystalline phase comprises a hole transporting material comprising two or more A conjugated substituted aryl or heteroaryl ring and one or more organic compounds of one or more thiol moieties. The method of claim 52, wherein the at least one hole or electron-conducting organic material suitable for forming an organic polycrystalline phase comprises a hole transporting material represented by the chemical formula (II) or (IV): Wherein R 'at each occurrence is independently selected from C ₁ -C ₁₀ alkyl, optionally substituted aryl or heteroaryl group. The method of claim 53, wherein the at least one organic material (which is a polymer binder of the organic semiconductor polycrystalline phase) comprises at least one hole or electron-conducting organic material suitable for forming an organic amorphous phase, The organic amorphous phase includes a randomly substituted poly(arylamine), and the polymer backbone of the poly(arylamine) contains an aryl moiety. The method of claim 52, wherein the ink is deposited on the substrate, wherein the forming step comprises an inkjet coating or spin coating step. The method of claim 52, wherein the at least one solvent is an organic solvent. The method of claim 52, wherein the at least one solvent is selected from the group consisting of tetrahydronaphthalene, chlorobenzene, dichlorobenzene, chloroform, and THF.