CN1739204B - Improvements in and relating to organic semiconductor materials - Google Patents

Abstract

The present invention discloses to a composition for use as an organic semiconducting (OSC) material, wherein the composition comprises: (i) at least one higher molecular weight organic semiconducting compound having a number average molecular weight (Mn) of at least 5000, and (ii) at least one lower molecular weight organic semiconducting compound having a number average molecular weight (Mn) of 1000 or less. Besides, the present invention also discloses use of the composition in an electronic device, such as FET or OLED and the like.

Description

Improved organic semiconductor materials and improvements related thereto

The present invention relates to a composition useful as an organic semiconductor (OSC) material, eg a layer comprising it used in electronic devices, a method for its production, its use and a device containing the composition.

In recent years, OSC materials have been developed to produce more diverse and lower-cost electronic devices. OSC materials may include either small organic molecules or polymers. This material finds application in a wide range of devices or devices, including organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs), photodetectors, photovoltaic (PV) cells, and in electrophotographic devices Used as an organic photoconductor (OPC), just to name a few.

In many applications of OSC materials, there is a need for increased charge carrier mobility that can lead to faster and/or more efficient devices.

Objects of the present invention include OSC materials providing improved mobility, and improved devices using the OSC materials. Other objects will become apparent from the following description.

Surprisingly, the inventors have found that a mixture of organic semiconducting compounds having several different molecular weights has a greater charge carrier mobility than any one compound alone. This is surprising because it was previously thought that by mixing two different semiconducting compounds, each with a different HOMO level, it would inevitably lead to charge trapping on one of the compounds, reducing mobility (see, Yokoyama and Yokoyama J .Appl.Phys.67(6)1990; Pai et al., J.Phys.Chem.88, p4714, 1984; Veres and Juhasz, Phil.Mag.B, Vol.75, No.3, pp.377-387, 1997 ).

According to a first aspect of the present invention, there is provided a composition for use as an OSC material, the composition comprising:

(i) at least one higher molecular weight organic semiconductor compound having a number average molecular weight (Mn) of at least 5000, and

(ii) At least one lower molecular weight organic semiconductor compound having a number average molecular weight (Mn) of 1000 or less.

Preferably, the Mn of the higher molecular weight semiconducting compound is at least 7000, preferably the Mn of the lower molecular weight semiconducting compound is at least 150.

Compositions with these molecular weight differences have been found to have increased charge carrier mobility compared to either higher or lower molecular weight compounds alone. In some cases, a doubling of the mobility was found.

Higher and lower molecular weight semiconductor compounds are transporters with the same type of charge carriers as each other. That is, the compounds are each either a so-called "p-type" compound capable of transferring positively charged holes, or each a so-called "n-type" compound capable of transferring negatively charged electrons, and the resulting compositions are respectively or p-class or n-class.

Both higher and lower molecular weight compounds are semiconducting compounds. Preferably at least one, more preferably both, of the higher and lower molecular weight semiconductor compounds have a charge carrier mobility μ of at least 10 ⁻⁵ cm ² /Vs, more preferably at least 10 ⁻⁴ cm ² /Vs. Preferably, at least the higher molecular weight semiconducting compound has a charge carrier mobility of at least 10 ⁻⁵ cm ² /Vs, more preferably at least 10 ⁻⁴ cm ² /Vs.

Preferably, the higher and lower molecular weight semiconducting compounds are in a relative ratio of 10:90-90:10 parts by weight, more preferably 30:70-70:30 parts by weight, even more preferably 40:60-60:40 parts by weight, and most preferably about 50:50 parts by weight are present in the composition.

Lower molecular weight compounds may comprise either oligomers with repeat unit numbers n ranging from 2 to 15, depending on the type of repeat unit, or non-oligomeric small molecules (ie, monomers, where n=1). In the case of lower molecular weight compounds including oligomers, n is more typically in the range of 2-5. Preferably, the lower molecular weight compounds are either oligomers where n=2 or 3 (i.e. dimers or trimers, respectively), or small non-oligomeric molecules where n=1 (i.e. monomers) . The term polymer is used herein to define any compound containing a number (>1) of repeating units. The aforementioned term oligomer is used herein additionally to define polymers having a smaller number of repeat units (typically 15 or less). The polymers (including oligomers) herein may be either monodisperse or polydisperse.

Preferably, the higher molecular weight semiconducting compound comprises a polymer, more preferably a π-conjugated polymer. The number n of repeating units of the polymer is typically 5 or higher, preferably 10 or higher, more preferably 15 or higher, and most preferably 20 or higher, depending on the type of repeating unit. The polymer may be substantially linear, or may have a degree of chain branching, or may contain crosslinks. Polymers can be either monodisperse or polydisperse.

The Mn of higher molecular weight semiconductor compounds can be, for example, at most 1.5×10 ⁶ . Mn can still be higher.

Preferably, the higher and lower molecular weight semiconducting compounds are of similar chemical class. In a preferred embodiment, the higher molecular weight compound contains one or more chemical groups that are the same or similar to those contained in the lower molecular weight compound. For example, preferably, the higher and lower molecular weight semiconducting compounds each collectively contain one or more of the following groups: arylamine, fluorene and/or thiophene groups. Among these groups, arylamines are more preferred, and triarylamines are even more preferred. Additionally or alternatively, the higher and lower molecular weight semiconducting compounds may contain the same or similar repeat units as each other.

A preferred class of lower molecular weight semiconducting compounds are those containing arylamine, fluorene and/or thiophene groups, more preferably arylamines, still more preferably triarylamines. A particularly preferred class of lower molecular weight semiconducting compounds are aromatic amine group-containing compounds having the following formula 1:

Formula 1

Wherein Ar ¹ , Ar ² and Ar ³ may be the same or different, and if they are in different repeating units, each independently represents optionally at least one optionally substituted C _1-40 hydrocarbon group and/or at least one other arbitrary Aryl (mono- or poly-nuclear) substituted by selected substituents, and n=1-4, preferably 1-3, and more preferably 1 or 2. Regarding Ar ¹ , Ar ² and Ar ³ , mononuclear aryl groups have only one aromatic ring, such as phenyl or phenylene. Polynuclear aryl groups have two or more aromatic rings, which may be fused aromatic rings (such as naphthyl or naphthylene), independently covalently linked aromatic rings (such as biphenyl) and/or fused aromatic rings. A combination of aromatic rings and independently linked aromatic rings. Preferably, each of Ar ¹ , Ar ² and Ar ³ is an aryl group substantially conjugated over substantially all groups.

Examples of compounds of Formula 1 are given below in the form of Formulas 2A-O:

Formula No. Compound

Other suitable lower molecular weight semiconducting compounds may include monomers where n=1 or oligomers where n=2-10, preferably n=2-3 (including copolymerization Oligomer):

Formula 3

Wherein R1 and R2 can be independently H; optionally substituted alkyl; alkoxy; thioalkyl; acyl; optionally substituted aryl; fluorine atom; Tertiary alkylamine or arylamine-N(R ₄ )(R ₅ ), wherein each of R ₄ and R ₅ can independently represent H, alkyl, substituted alkyl, aryl, substituted aryl, alkoxy or polyalkylene oxy; or other substituents, and * is any terminal or capping group including hydrogen. Alkyl and aryl groups can be optionally fluorinated.

Formula 4

Wherein X can be Se, Te or preferably O, S or -N(R)-, wherein R represents H, alkyl, substituted alkyl, aryl or substituted aryl; R1 and R2 are the same as in formula 3. Alkyl and aryl groups can be optionally fluorinated.

Formula 5

wherein X, R1 and R2 are the same as in formula 3.

Formula 6

wherein X is the same as in Formula 4; R1 and R2 are the same as in Formula 3; and Z represents -C(T ₁ )=C(T ₂ )-, -C≡C-, -N(R')-, -N=N-, (R')=N-, -N=C(R')-, T ₁ and T ₂ independently represent -H, Cl, F, -C≡N- or lower alkyl, R ' represents -H, alkyl, substituted alkyl, aryl or substituted aryl. Alkyl and aryl groups may also be optionally fluorinated.

Formula 7

wherein R1 and R2 are the same as in formula 3. Alkyl and aryl groups can be optionally fluorinated.

Formula 8

Wherein R1-R4 can be independently selected from the same exemplary groups as R1 and R2 in formula 3.

Formula 9

Wherein the monomer is an anilino-based monomer unit, and the groups Ar', Ar" and Ar"' are optionally substituted aryl groups, wherein the aryl group can be phenyl and Ar"' can be substituted with an electron-withdrawing or electron-donating effect Group substitution (eg, ortho or para substitution).

A preferred class of higher molecular weight semiconducting compounds includes those substantially comprising π-conjugated repeat units. The higher molecular weight semiconducting compounds can be homopolymers or copolymers (including block copolymers) of the general formula 10:

A _(c) B _(d) ... X _(z) Formula 10

Wherein A, B, ..., Z each represent a monomer unit, and (c), (d), ... (z) each represent a fraction of each monomer unit in the polymer, i.e. each (c), (d) , ...(z) is a value of 0-1, and the sum of (c)+(d)+...+(z) is equal to 1. Examples of monomeric units A, B, ..., Z include units of formulas 3-9 given above. In the case of block copolymers, each monomer A, B, ..., Z may be a conjugated oligomer or polymer comprising, for example, 2-50 units of formula 3-9. Higher molecular weight semiconducting compounds preferably include arylamines, fluorenes, thiophenes, spirobifluorenes and/or optionally substituted aryls (eg phenylenes), more preferably arylamines, still more preferably triarylamines. The aforementioned groups may be linked via further conjugated groups such as vinylidene. In addition, preferred higher molecular weight semiconducting compounds include polymers (or homopolymers or copolymers, including block copolymers) containing one or more of the aforementioned arylamines, fluorenes, thiophenes, and/or optionally substituted aryl groups ). Preferred higher molecular weight compounds include homopolymers or copolymers (including block copolymers) containing arylamine (preferably triarylamine) and/or fluorene units. Another preferred higher molecular weight compound includes homopolymers or copolymers (including block copolymers) containing fluorene and/or thiophene units. Examples of copolymers of higher molecular weight compounds are given below:

Copolymer Example i

Copolymer Example ii

A particularly preferred class of higher molecular weight semiconducting compounds are polymers containing the same arylamine groups as in Formula 1 above, except that n is at least 5, preferably at least 10, more preferably at least 15 and most preferably At least 20. This compound is represented here as Formula 11. An example of a series of compounds of Formula 11 has Formulas 11A-C, wherein n is at least 15.

Formula 11A

Formula 11B

Formula 11C

Compounds of formulas 1 and 11 can be prepared by various methods including those described in WO99/32537 and WO00/78843, the contents of which are incorporated herein by reference.

Particularly preferred compositions according to the invention contain at least one compound of formula 1 (preferably where n=1 or 2) as lower molecular weight compound and at least one compound of formula 11 (preferably where n is at least 20) as higher molecular weight compound. molecular weight compounds. An even more particularly preferred composition is one in which the compounds of the aforementioned formulas 1 and 11 are provided in parts by weight in a relative ratio of 40:60 to 60:40.

Advantageously, such compositions of the invention may exhibit improved carrier mobility, good solubility for solution coating techniques, compatibility with adhesives and/or high durability.

The compositions of the present invention may be prepared by a process comprising mixing at least one higher molecular weight compound and at least one lower molecular weight compound together in a solvent. The solvent can be one solvent, or the higher and lower molecular weight compounds can each be dissolved in separate solvents, and the two resulting solutions can then be combined to combine the compounds. A solvent containing the compound can then be applied to the substrate. The solvent can be evaporated to form the composition.

Preferably, the composition of the invention and/or the individual higher and lower molecular weight compounds making up the composition can be deposited from a solvent. The solvent can be evaporated to form a composition. Preferably, the composition and/or the individual higher and lower molecular weight compounds making up the composition are soluble in the solvent. Preferably, the composition and the individual higher and lower molecular weight compounds making up the composition are soluble in a wide range of organic solvents such as, without limitation, toluene, THF, ethyl acetate, dichloro Methane, chlorobenzene, anisole, xylene. Accordingly, the composition can be applied to a substrate as part of a fabricated device by various solution coating methods. Various coating or printing techniques such as dip coating, roll coating, reverse roll coating, rod coating, spin coating, gravure coating, lithographic coating (including photolithography), inkjet coating ( These include continuous and drop-on-demand, and firing by piezoelectric or thermal methods), screen coating, spray coating, and web coating to apply the composition to the substrate. The composition can be deposited as a layer or film.

In one embodiment, the higher molecular weight compound may be deposited on the substrate first (e.g., by solution coating) followed by deposition of the lower molecular weight compound (e.g., by the same or a different solution coating than in the first step). layer and allow the lower molecular weight compound to diffuse into the higher molecular weight compound to form the composition, or vice versa.

The invention also provides the use of the composition in electronic devices. The composition can be used as a high mobility semiconductor material in various devices and devices. The composition can be used, for example, in the form of a semiconducting layer or film. Accordingly, in a further aspect the invention provides a layer for use in an electronic device, the layer comprising the composition of the first aspect of the invention. The layer or film can be smaller than about 30 microns. For various electronic device applications, the thickness can be less than about 1 micron thick. The layer may be deposited, eg, on a portion of an electronic device, by any of the aforementioned solution coating or printing techniques.

Can be in a field effect transistor (FET), for example as a layer or film, for example as a semiconductor channel, an organic light emitting diode (OLED), for example as a hole or electron injection or transport layer or an electroluminescent layer, a photodetector, a chemical detector, Photovoltaic cells (PV), capacitors, memory devices, etc. use the composition. The composition can also be used in electrophotographic (EP) devices, for example in organic photoconductors. Solution coating of the composition is preferred to form a layer or film within the aforementioned device or device, offering advantages in terms of cost and manufacturing versatility. The improved charge carrier mobility of the compositions of the invention allows for faster and/or more efficient operation of such devices or devices.

It is to be understood that the compositions of the present invention may be formulated differently with different amounts of composition and/or additional ingredients depending on the end use. The composition of the invention may be used in combination with a diluent, such as at least one binder resin and/or another OSC material.

The composition may be used in conjunction with a binder resin to further improve film formation and/or to adjust viscosity to improve the coatability of the solution. The adhesive may also optionally be crosslinked for improved laminate integrity of the layers. Preferred binders are electrical insulators. Preferred binders include, without limitation, at least one of polyamides, polyurethanes, polyethers, polyesters, epoxies, polyketones, polycarbonates, polysulfones, vinyl polymers such as polyvinyl ketone and/or polyvinyl butyral), polystyrene, polyacrylamide, copolymers thereof (such as aromatic copolymer polycarbonate polyester), and/or combinations thereof. Further suitable adhesives are disclosed in WO 02/45184.

Definitions of various terms used herein are now explained.

As used herein, n is the number of repeating units that can be present in a particular polymer or oligomer.

In any polymer or oligomer formula given herein, the polymer or oligomer may have any terminal or capping group, including hydrogen.

The term "at least one" in reference to "at least one higher molecular weight semiconducting compound" or "at least one lower molecular weight semiconducting compound" should be clearly understood to mean that two or more one higher molecular weight semiconducting compound and/or two or more lower molecular weight semiconducting compounds.

One or more aryl groups Ar ¹ , Ar ² and Ar ³ in formulas 1 and 2 are optionally substituted by at least one optionally substituted C _1-40 hydrocarbon group, wherein the C _1-40 hydrocarbon group is preferably C _{1- 10} hydrocarbyl, more preferably C _1-4 hydrocarbyl. Also preferably, the hydrocarbyl group is an optionally substituted alkyl group. For optionally substituted C _1-40 hydrocarbyl, optionally substituted C _1-4 alkyl is most preferred.

When symbols (such as Ar ¹ , Ar ² and Ar ³ ) or subscripts (such as 'n') are specified in the chemical formulas herein, they are considered to represent groups or series of values, and these "in each independently in each case", means that each symbol and/or subscript can represent each group independently of each other, independently within each repeating unit, independently within each chemical formula and/or in each group that is optionally substituted Any of those groups independently listed on the group. Thus, in each case of these examples, a number of different groups can be represented by a single symbol (eg Ar ¹ ).

As used herein, the terms 'substituent', 'substituted', 'optional substituent' and/or 'optionally substituted' (unless other substituents are listed next) mean that at least one of the following groups (or substituted by these groups): sulfo, sulfonyl, formyl, amino, imino, nitroso, mercapto, cyano, nitro, halogen, C _1-4 alkyl, C _1-4 alkoxy, Hydroxyl and/or combinations thereof. These optional groups may include all chemically possible combinations and/or a plurality (preferably 2) of the aforementioned groups within the same group (eg amino and sulfonyl if directly attached to each other represent sulfamoyl). Preferred optional substituents include: any C _1-4 alkyl, methoxy and/or ethoxy (any of these optionally substituted by at least one halogen); and/or amino (optional substituted by at least one methyl and/or ethyl group); and/or halogen.

The term 'hydrocarbyl' as used herein means any radical moiety comprising at least one hydrogen atom and at least one carbon atom. However, hydrocarbyl groups may be optionally substituted. Preferably, 'hydrocarbyl' comprises at least one of the following carbon-containing moieties: alkyl, alkoxy, alkanoyl, carboxyl, carbonyl, formyl and/or combinations thereof; and optionally in combination with at least one of the following heteroatoms Moieties of: oxy, thio, sulfinyl, sulfonyl, amino, imino, nitroso and/or combinations thereof. More preferred hydrocarbyl groups include at least one: (optionally substituted by at least one halogen) alkyl and/or alkoxy.

As used herein, the term "alkyl" can readily be used to denote terms of different degrees of saturation and/or valence, such as moieties including double bonds, triple bonds, and/or aromatic moieties (e.g., alkenyl, alkyne, radical and/or aryl) and polyvalent species (such as alkylene) attached to two or more substituents.

The term 'halogen' as used herein means fluorine, chlorine, bromine and iodine.

Any group or moiety mentioned herein (e.g. as a substituent) refers to a monovalent group, unless otherwise stated, or unless the context clearly dictates otherwise (e.g. an alkylene moiety is divalent and links two other part). Unless the context clearly indicates otherwise, a group comprising a chain of three or more atoms herein refers to a group in which all or part of the chain may be straight, branched and/or form a ring (including spiro and/or fused ring) groups.

Unless the context clearly dictates otherwise, the plural forms of the terms used herein are to be construed as including the singular form and vice versa.

In the description and claims of this specification, the words "comprises" and "comprises" and variations of the words, such as "including" and "comprises" mean, "including, but not limited to", and are not intended to ( and does not) exclude other components.

It will be appreciated that variations of the foregoing embodiments of the invention may be made and still fall within the scope of the invention. Each feature disclosed in this specification, unless stated otherwise, may be replaced by an alternative feature serving the same, equivalent or similar purpose. Thus, unless stated otherwise, each feature disclosed is only one example of a generic series of equivalent or similar features.

All features disclosed in this specification may be combined in any combination, except combinations in which at least some of such features and/or steps are mutually exclusive. In particular, preferred features of the invention are applicable to all aspects of the invention and in any combination. Likewise, features described in non-essential combinations may be used independently (not in combination).

It is to be understood that many of the features described above, particularly the preferred embodiments, are inventive in their own right and are not merely part of the embodiments of the invention. Independent protection may be sought for these features in addition to any invention presently claimed or alternatives thereof.

The present invention will now be described in more detail by referring to the following examples, which are merely illustrative and do not limit the scope of the present invention.

Determination of Field Effect Mobility

The materials were tested for field effect mobility using the technique described by Holland et al. in J. Appl. Phys. Vol. 75, p. 7954 (1994).

In the following examples, test field effect transistors (FETs) were fabricated on prepatterned Pt/Pd source and drain electrodes on polyester substrates. The channel length (L) (=distance between electrodes) was 100 microns, and the channel width (W) was 36 mm. 1 part of the inventive semiconductor composition (high and low molecular weight compounds) is dissolved in 99 parts of solvent, typically toluene, and spin-coated on a substrate at 1000 rpm for 20 seconds to give a film of about 100 nm. To ensure complete drying, the sample was placed in an oven at 100°C for 20 minutes. A solution of a low dielectric constant perfluoropolymer, Cytop 107M (Asahi Glass, Z-1700E01), was then spin-coated on the semiconductor to obtain a thickness typically in the range of 0.5 micron to 1 micron. The sample was again placed in an oven at 100°C to evaporate the solvent from the insulator. On the device channel area, a gold gate contact point is defined by means of evaporation through a shadow mask. To determine the capacitance of the insulator layer, a number of devices were prepared consisting of an unpatterned Pt/Pd base layer, an insulator layer prepared in the same manner as on the FET device, and a top electrode of known geometry. Measure the capacitance with a handheld multimeter attached to the metal on either side of the insulator.

The voltage applied to the transistor is the potential with respect to the source electrode. In the case of p-type gate materials, when a negative potential is applied to the gate, positive charge carriers (holes) accumulate within the semiconductor on the other side of the gate insulator. (For an n-channel FET, apply a positive voltage). This is called cumulative mode. The capacitance/area _Ci of the gate insulator determines the amount of charge thus induced. When a negative potential V _DS is applied to the drain electrode, the accumulated carriers generate a source-drain current I _DS , _which depends mainly on the density of the accumulated carriers and, importantly, their mobility. Geometric factors such as the structure, size and distance of the drain and source electrodes also affect the current flow. Typically, the range of gate and drain voltages is recorded during the study of the device. The source-drain current is described by Equation 1.

$I_{\mathrm{DS}}=\frac{{\mathrm{\μWC}}_i}{L}((V_G-V_0)V_{\mathrm{DS}}-\frac{V_{\mathrm{DS}}^2}{2})+I_{\mathrm{\Ω}},$ Formula 1

where _V0 is the offset voltage, and _IΩ is the ohmic current independent of the gate voltage and due to the finite conductivity of the material. Other parameters are described above.

For electrical measurements, mount the transistor sample on the sample holder. Microprobes were connected to the gate, drain and source electrodes using a Karl Suss PH100 microprobe. These were connected to a Hewlett-Packard 4155B Parameter Analyzer. The drain voltage is initially set to -2V, and the gate voltage is swept from +20 to -40V in 1V steps, then, V _D is set to -20V, and the gate voltage is swept from +20V to -40V for the second time. When V _G >V _DS , the source-drain current varies linearly with V _G. Therefore, the field-effect mobility can be calculated from the gradient change (S) of I _DS versus V _G given by Equation 2.

$S=\frac{{\mathrm{\μWC}}_i{V}_{\mathrm{DS}}}{L}$ formula 2

All field effect mobilities listed below (unless otherwise stated) were calculated according to this method.

Example 1

Mixtures 1-6 were made from the high and low molecular weight compounds listed in Table 1 (50:50 parts by weight). The mobility of the resulting mixture is given along with the % increase in mobility compared to the individual components. It can be seen that a significant increase in mobility is obtained with the mixtures, and in the case of mixtures 3 and 5 the mobility is more than doubled. This experiment tested compounds of formula 11A with molecular weights up to about 19000, all of which showed increased mobility effects.

Table 1

Mixture No. High molecular weight compounds (mobility, cm ² /VS) Low molecular weight compounds (mobility, cm ² /VS) The mobility of the mixture % Increase in Mobility* 1 Formula 11A, Mn=17300 (4.0×10 ^-3 ) Formula 2C, Mn=542 (3.2×10 ^-4 ) 6.0×10 ^-3 50 2 Formula 11A, Mn=17300 (4.0×10 ^-3 ) Formula 2A, Mn=514(3.7×10 ^-4 ) 7.3×10 ^-3 83 3 Formula 11A, Mn=17300 (4.0×10 ^-3 ) Formula 2J, Mn=359(1.0×10 ^-3 ) 8.8×10 ^-3 120

4 Formula 11A, Mn=17300 (4.0×10 ^-3 ) Formula 2I, Mn=389(1.0×10 ^-3 ) 7.3×10 ^-3 83 5 Formula 11A, Mn=19100 (3.2×10 ^-3 ) Formula 2A, Mn=514(3.7×10 ^-4 ) 7.0×10 ^-3 118 6 Formula 11A, Mn=10200 (2.9×10 ^-3 ) Formula 2A, Mn=514(3.7×10 ^-4 ) 5.3×10 ^-3 83

*Compared to the mobility of the high molecular weight component itself

Example 2

Further mixtures in Table 2 were made using the high molecular weight material of formula 11A with Mn = 17300 and the various low molecular weight compounds listed (50:50 parts by weight). The % increase in mobility of the resulting mixture compared to the mobility of the high molecular weight component itself is given.

Table 2

Mixture No. low molecular weight compound % increase in mobility compared to the Mn=17300 compound of formula 11A 7 Formula 2B, Mn=588 39% 8 Formula 2D, Mn=516 37% 9 Formula 2E, Mn=488 64% 10 Formula 2F, Mn=544 17% 11 Formula 2K, Mn=361 60% 12 Formula 2L, Mn=564 25% 13 Formula 2M, Mn=544 36%

Example 3

Using the compound of formula 2A as the low molecular weight compound, a series of mixtures were made containing high molecular weight compounds of general formula 11A with increasing molecular weights. The mixture is 50:50 parts by weight. Figure 1 shows the results. Mixtures containing compounds of formula 11A with a molecular weight = 2000-3000 or less have impaired mobility compared to the single components. However, for molecular weights of about 5000 or greater, the mobility of the mixture increases significantly compared to the high molecular weight component itself.

Examples 4 and 5

Study the mobility as a function of the mixing ratio of high and low molecular weight compounds. The high molecular weight compound of formula 11A (Mn=17300) was mixed with the low molecular weight compound of formula 2C at various mixing ratios (Example 4). Figure 2 shows the results. The experiment was repeated using a different low molecular weight compound, now the compound of formula 2J (Example 5), and Figure 3 shows the results. It can be seen that the greatest increase in mobility occurs when the mixing ratio ranges from 40:60 to 60:40 parts by weight, especially at a ratio of about 50:50.

Comparative example 1

From the high and low molecular weight compounds listed in Table 3 (50:50 parts by weight), non-inventive mixtures 14 and 15 were made. The mobilities and percent changes of the resulting mixtures are given when compared to the high molecular weight compound itself. The mobility of the mixture was found to be lower than that of the component itself.

table 3

Mixture No. High molecular weight compounds (mobility, cm ² /VS) Low molecular weight compounds (mobility, cm ² /VS) The mobility of the mixture Change in Mobility %* 14 contrast Formula 11A, Mn=2500(2.3×10 ^-3 ) Formula 2A, Mn=514(3.7×10 ^-4 ) 1.1×10 ^-3 -52 15 contrast Formula 11B, Mn=2100(4.1×10 ^-3 ) Formula 2A, Mn=514(3.7×10 ^-4 ) 2.9×10 ^-3 -30

Example 6

Mixtures 16 and 17 were made from the high and low molecular weight compounds listed in Table 4 (50:50 parts by weight). These experiments were performed using chlorobenzene as the solvent for the organic semiconductor mixture. The dielectric used was polyisobutylene (Acroscat. No. 29916-1000) spun from hexane solution. When the dielectric thickness was greater than in the previous examples, a gate potential of -60V was used instead of -40V to measure mobility. The mobilities of the resulting mixtures are given together with the % increase compared to the single components. It can be seen that a significant increase in mobility is obtained with the mixture.

Table 4

Mixture No. High molecular weight compounds (mobility, cm ² /VS) Low molecular weight compounds (mobility, cm ² /VS) The mobility of the mixture % Increase in Mobility* 16 Formula 11C, Mn=50000(3.0×10 ^-3 ) Formula 2J, Mn=359(1.0×10 ^-3 ) 4.8×10 ^-3 60 17 Formula 11C, Mn=50000(3.0×10 ^-3 ) Equation 20, Mn = 345 (measurement of mobility not possible on its own due to the crystalline nature of the film) 4.4×10 ^-3 47

Example 7

Using the method of Example 6 above, mixtures 18 and 19 were produced from the high molecular weight and low molecular weight compounds (50:50 parts by weight) listed in Table 5, except that in the case of mixture 18, the dielectric was obtained from a toluene solution Spun CYTOP. The PIB dielectric in mixture 19 was spun from toluene. Measurements were performed as in Example 6 above. Table 5 gives the mobilities of the resulting mixtures and the % increase compared to the individual components. It can be seen that a significant increase in mobility is again obtained with the mixture. The high molecular weight compound in this case is a copolymer (the following formulas 12A and 12B).

table 5

Mixture No. High molecular weight compounds (mobility, cm ² /VS) Low molecular weight compounds (mobility, cm ² /VS) Mobility of the mixture (cm ² /VS) % increase in mobility 18 Formula 12A, Mn=8200(7.3×10 ^-4 ) Formula 2C (1.7×10 ^-3 ) 133 19 Formula 12B, Mn=17900 (2.8×10 ^-3 ) Formula 2J (4.7×10 ^-3 ) 68

Formula 12A

Formula 12B

Claims (27)

1. composition as organic semiconductor material, said composition comprises:

(i) number-average molecular weight be at least 5000 at least a higher molecular weight organic semiconductor compound and

(ii) number-average molecular weight is 1000 or the organic semiconductor compound of at least a lower molecular weight still less, and wherein the semiconductor compound of lower molecular weight has formula 1:

Formula 1

Ar wherein ¹, Ar ³And Ar ³Can be identical or different, if in different repeating units, then represent unsubstituted independently of one another or by at least one C _1-40Monokaryon or multinuclear aryl that other substituting group of alkyl and/or at least one replaces, and n=1-4, described other substituting group is selected from sulfo group, alkylsulfonyl, formyl radical, amino, imino-, nitroso-group, sulfydryl, cyano group, nitro, halogen, C _1-4Alkyl, C _1-4Alkoxyl group and/or hydroxyl.

2. the composition of claim 1, wherein the Mn of the semiconductor compound of higher molecular weight is at least 7000.

3. the composition of claim 2, wherein the Mn of the semiconductor compound of lower molecular weight is at least 150.

4. the composition of claim 1, at least a charge carrier mobility μ in the semiconductor compound of wherein higher and lower molecular weight is at least 10 ^-5Cm ²/ V.s.

5. the composition of claim 4, wherein said charge carrier mobility μ is at least 10 ^-4Cm ²/ V.s.

6. the composition of claim 4, wherein the semiconductor compound of higher molecular weight has described charge carrier mobility at least.

7. the composition of claim 4, the two all has described charge carrier mobility the semiconductor compound of wherein higher and lower molecular weight.

8. the composition of claim 1, the semiconductor compound of wherein higher and lower molecular weight is with 10: 90-90: the relative proportion of 10 weight parts is present in the composition.

9. the composition of claim 8, the semiconductor compound of wherein higher and lower molecular weight is with 30: 70-70: the relative proportion of 30 weight parts is present in the composition.

10. the composition of claim 9, the semiconductor compound of wherein higher and lower molecular weight is with 40: 60-60: the relative proportion of 40 weight parts is present in the composition.

11. the composition of claim 1, wherein the semiconductor compound of higher molecular weight comprises conjugated polymers.

12. the composition of claim 11, wherein the semiconductor compound of higher molecular weight comprises the polymkeric substance as homopolymer or multipolymer that contains one or more arylamine, fluorenes, thiophene and/or replacement or unsubstituted aryl, comprising segmented copolymer.

13. the composition of claim 12, wherein polymkeric substance is to contain arylamine and/or unitary homopolymer of fluorenes or multipolymer, comprising segmented copolymer.

14. the composition of claim 12, wherein polymkeric substance is homopolymer or the multipolymer that contains fluorenes and/or thiophene unit, comprising segmented copolymer.

15. the composition of claim 12, wherein polymkeric substance is the polymkeric substance that contains the formula 11 of aryl amine, and its Chinese style 11 is identical with formula 1, and different is that n is at least 5.

16. the composition of claim 15, wherein n is at least 20.

17. the composition of claim 1, wherein higher and semiconductor compound lower molecular weight contains one or more following radicals separately jointly: arylamine, fluorenes and/or thiophene.

18. the composition of claim 1, comprise n=1 wherein or 2 at least a formula 1 compound as the compound of lower molecular weight and wherein n be the compound of at least 20 at least a formula 11 compound as higher molecular weight.

19. the composition of claim 1 further comprises adhesive resin.

20. the purposes of each composition in electron device among the claim 1-19.

21. the purposes of claim 20, wherein said electron device are electric photographic means.

22. be used for the layer of electron device, wherein this layer comprises among the claim 1-19 each composition.

23. the layer of claim 21 wherein deposits this layer by solution coat on the electron device of a part.

24. the layer of claim 21 wherein deposits this layer by one of following coating or printing technology on a part of electron device: dip-coating, roller coat, inverse roller coating, rod are coated with, spin coating, gravure coating, planography coating, ink-jet application, sieve are coated with, spraying and reticulate pattern coating.

25. the layer of claim 22, wherein one of compound by at first depositing higher and lower molecular weight then deposits another higher and compound lower molecular weight, and the compound that makes higher and lower molecular weight is at internal diffusion each other, form composition, thereby deposit this layer.

26. the layer of claim 22, wherein in one of following electron device, this layer is used as semiconductor layer: field-effect transistor, Organic Light Emitting Diode, photodetector, chemical detector, barrier-layer cell, electrical condenser, memory device or electric photographic means.

27. the layer of claim 26, wherein said electric photographic means is an organic photoconductor.

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