Organic semiconductor device and process for its production

Abstract

An organic semiconductor device selected from organic diodes, organic field effect transistors, and devices comprising an organic diode and/or organic field effect transistor and a method of producing such a device are provided. The organic semiconductor device comprises at least one semiconducting layer based on a diketopyrrolopyrrole (DPP) polymer. The semiconducting layer may effectively be protected against degradation by radiation and/or oxidation by adding at least one stabilizing agent selected from hydroxybenzophenones, hydroxyphenyl benzotriazoles, oxalic acid anilides, hydroxyphenyl triazines, hindered phenols and/or merocyanines to the DPP polymer layer. The stabilization is effective both during production and during usage of the device, while the device's electronic properties are retained. The stabilizing agent is preferably a UV absorbing agent or an antioxidant or anti-radical agent known from the field of organic polymer technology.

Claims

1. An organic semiconductor device, comprising: at least one of an organic diode and an organic field effect transistor, wherein the at least one of the organic diode and the organic field effect transistor comprises a semiconducting layer comprising a mixture comprising a diketopyrrolopyrrole (DPP) polymer and a stabilizing agent, the stabilizing agent being included in the mixture in an amount of from 0.0005 to 0.1 parts by weight per 1 part by weight of the DPP polymer, and the stabilizing agent is selected from the group consisting of a UV absorbing agent, an antioxidant, and an anti-radical agent.

2. The device of claim 1, wherein the stabilizing agent is at least one selected from the group consisting of a hydroxybenzophenone, a hydroxyphenyl benzotriazole, an oxalic acid anilide, a hydroxyphenyl triazine, a hindered phenole, and a merocyanine.

3. The device of claim 1, wherein the stabilizing agent comprises a UV absorbing agent selected from the group consisting of: a 2-hydroxybenzophenone of formula I ##STR00096## a 2-hydroxyphenylbenzotriazole of formula IIa, IIb or IIc ##STR00097## a 2-hydroxyphenyltriazine of formula III ##STR00098## an oxanilide of formula IV ##STR00099## and a merocyanine of formula V ##STR00100## each including E,E-, E,Z- and Z,Z-geometrical isomers thereof; wherein in formula I, v is an integer from 1 to 3, w is 1 or 2, and the substituents Z independently of one another are hydrogen, halogen, hydroxyl or alkoxy having 1 to 12 carbon atoms; in formula IIa, R.sub.1 is hydrogen, alkyl having 1 to 24 carbon atoms, phenylalkyl having 1 to 4 carbon atoms in the alkyl moiety, cycloalkyl having 5 to 8 carbon atoms or a radical of formula ##STR00101## in which R.sub.4 and R.sub.5 independently of one another are alkyl having 1 to 5 carbon atoms, or R.sub.4, together with the radical C.sub.nH.sub.2n+1m, forms a cycloalkyl radical having 5 to 12 carbon atoms, m is 1 or 2, n is an integer from 2 to 20, and M is a radical of formula COOR.sub.6 in which R.sub.6 is hydrogen, alkyl having 1 to 12 carbon atoms, alkoxyalkyl having in each case 1 to 20 carbon atoms in the alkyl moiety and in the alkoxy moiety or phenylalkyl having 1 to 4 carbon atoms in the alkyl moiety, R.sub.2 is hydrogen, halogen, alkyl having 1 to 18 carbon atoms, alkyl of 2 to 4 carbon atoms substituted by C.sub.2-C.sub.6alkanoyloxy or C.sub.3-C.sub.6alkenoyloxy, or phenylalkyl having 1 to 4 carbon atoms in the alkyl moiety, and R.sub.3 is hydrogen, halogen, alkyl or alkoxy having in each case 1to 4 carbon atoms or COOR.sub.6 in which R.sub.6 is as defined above, at least one of the radicals R.sub.1 and R.sub.2 being other than hydrogen; in formula IIb, T is hydrogen or alkyl having 1 to 6 carbon atoms, T.sub.1 is hydrogen, chloro or alkyl or alkoxy having in each case 1to 4 carbon atoms, n is 1 or 2 and, if n is 1, T.sub.2 is chloro or a radical of the formula OT.sub.3 or ##STR00102## and, if n is 2, T.sub.2 is a radical of the formula ##STR00103## or O-T.sub.9-O; in which T.sub.3 is hydrogen, alkyl which has 1 to 18 carbon atoms and is unsubstituted or substituted by 1 to 3 hydroxyl groups or by OCOT.sub.6, alkyl which has 3 to 18 carbon atoms, is interrupted once or several times by Oor NT.sub.6- and is unsubstituted or substituted by hydroxyl or OCOT.sub.6, cycloalkyl which has 5 to 12 carbon atoms and is unsubstituted or substituted by hydroxyl and/or alkyl having 1 to 4 carbon atoms, alkenyl which has 2 to 18 carbon atoms and is unsubstituted or substituted by hydroxyl, phenylalkyl having 1 to 4 carbon atoms in the alkyl moiety, or a radical of formula CH.sub.2CH(OH)-T.sub.7 or ##STR00104## T.sub.4 and T.sub.5 independently of one another are hydrogen, alkyl having 1 to 18 carbon atoms, alkyl which has 3 to 18 carbon atoms and is interrupted once or several times by Oor NT.sub.6-, cycloalkyl having 5 to 12 carbon atoms, phenyl, phenyl which is substituted by alkyl having 1 to 4 carbon atoms, alkenyl having 3 to 8 carbon atoms, phenylalkyl having 1 to 4 carbon atoms in the alkyl moiety or hydroxyalkyl having 2 to 4 carbon atoms, T.sub.6 is hydrogen, alkyl having 1 to 18 carbon atoms, cycloalkyl having 5 to 12 carbon atoms, alkenyl having 3 to 8 carbon atoms, phenyl, phenyl which is substituted by alkyl having 1 to 4 carbon atoms, phenylalkyl having 1 to 4 carbon atoms in the alkyl moiety, T.sub.7 is hydrogen, alkyl having 1 to 18 carbon atoms, phenyl which is unsubstituted or substituted by hydroxyl, phenylalkyl having 1 to 4 carbon atoms in the alkyl moiety, or CH.sub.2OT.sub.8, T.sub.8 is alkyl having 1 to 18 carbon atoms, alkenyl having 3 to 8 carbon atoms, cycloalkyl having 5 to 10 carbon atoms, phenyl, phenyl which is substituted by alkyl having 1 to 4 carbon atoms, or phenylalkyl having 1 to 4 carbon atoms in the alkyl moiety, T.sub.9 is alkylene having 2 to 8 carbon atoms, alkenylene having 4 to 8 carbon atoms, alkynylene having 4 carbon atoms, cyclohexylene, alkylene which has 2 to 8 carbon atoms and is interrupted once or several times by O, or a radical of the formula CH.sub.2CH(OH)CH.sub.2OT.sub.11OCH.sub.2CH(OH)CH.sub.2or CH.sub.2C(CH.sub.2OH).sub.2CH.sub.2, T.sub.10 is alkylene which has 2 to 20 carbon atoms and can be interrupted once or several times by O, or cyclohexylene, T.sub.11 is alkylene having 2 to 8 carbon atoms, alkylene which has 2 to 18 carbon atoms and is interrupted once or several times by O, 1,3-cyclohexylene, 1,4-cyclohexylene, 1,3-phenylene or 1,4-phenylene, or T.sub.10 and T.sub.6, together with the two nitrogen atoms, are a piperazine ring; in formula IIc, R.sub.2 is C.sub.1-C.sub.12alkyl and k is a number from 1 to 4; in formula III, u is 1 or 2 and r is an integer from 1 to 3, Y.sub.1 independently of one another are hydrogen, hydroxyl, phenyl or halogen, halogenomethyl, alkyl having 1 to 12 carbon atoms, alkoxy having 1 to 18 carbon atoms, alkoxy having 1 to 18 carbon atoms which is substituted by a group COO(C.sub.1-C.sub.18alkyl); if u is 1, Y.sub.2 is alkyl having 1 to 18 carbon atoms, phenyl which is unsubstituted or substituted by hydroxyl, halogen, alkyl or alkoxy having 1 to 18 carbon atoms; alkyl which has 1 to 12 carbon atoms and is substituted by COOH, COOY.sub.8, CONH.sub.2, CONHY.sub.9, CONY.sub.9Y.sub.10, NH.sub.2, NHY.sub.9, NY.sub.9Y.sub.10, NHCOY.sub.11, CN and/or OCOY.sub.11; alkyl which has 4 to 20 carbon atoms, is interrupted by one or more oxygen atoms and is unsubstituted or substituted by hydroxyl or alkoxy having 1 to 12 carbon atoms, alkenyl having 3 to 6 carbon atoms, glycidyl, cyclohexyl which is unsubstituted or substituted by hydroxyl, alkyl having 1 to 4 carbon atoms and/or OCOY.sub.11, phenylalkyl which has 1 to 5 carbon atoms in the alkyl moiety and is unsubstituted or substituted by hydroxyl, chlorine and/or methyl, COY.sub.12 or SO.sub.2Y.sub.13, or, if u is 2, Y.sub.2 is alkylene having 2 to 16 carbon atoms, alkenylene having 4 to 12 carbon atoms, xylylene, alkylene which has 3 to 20 carbon atoms, is interrupted by one or more O atoms and/or is substituted by hydroxyl, CH.sub.2CH(OH)CH.sub.2OY.sub.15OCH.sub.2CH(OH)CH.sub.2, COY.sub.16CO, CONHY.sub.17NHCOor (CH.sub.2).sub.mCO.sub.2Y.sub.18OCO(CH.sub.2).sub.m, in which m is 1, 2 or 3, Y.sub.8 is alkyl having 1 to 18 carbon atoms, alkenyl having 3 to 18 carbon atoms, alkyl which has 3 to 20 carbon atoms, is interrupted by one or more oxygen or sulfur atoms or NT.sub.6- and/or is substituted by hydroxyl, alkyl which has 1 to 4 carbon atoms and is substituted by P(O)(OY.sub.14).sub.2, NY.sub.9Y.sub.10 or OCOY.sub.11 and/or hydroxyl, alkenyl having 3 to 18 carbon atoms, glycidyl, or phenylalkyl having 1 to 5 carbon atoms in the alkyl moiety, Y.sub.9 and .sub.Y10 independently of one another are alkyl having 1 to 12 carbon atoms, alkoxyalkyl having 3 to 12 carbon atoms, dialkylaminoalkyl having 4 to 16 carbon atoms or cyclohexyl having 5 to 12 carbon atoms, or Y.sub.9 and Y.sub.10 together are alkylene, oxaalkylene or azaalkylene having in each case 3to 9 carbon atoms, Y.sub.11 is alkyl having 1 to 18 carbon atoms, alkenyl having 2 to 18 carbon atoms or phenyl, Y.sub.12 is alkyl having 1 to 18 carbon atoms, alkenyl having 2 to 18 carbon atoms, phenyl, alkoxy having 1 to 12 carbon atoms, phenoxy, alkylamino having 1 to 12 carbon atoms or phenylamino, Y.sub.13 is alkyl having 1 to 18 carbon atoms, phenyl or alkylphenyl having 1 to 8 carbon atoms in the alkyl radical, Y.sub.14 is alkyl having 1 to 12 carbon atoms or phenyl, Y.sub.15 is alkylene having 2 to 10 carbon atoms, phenylene or a group -phenylene-M-phenylene-in which M is O, S, SO.sub.2, CH.sub.2or C(CH.sub.3).sub.2, Y.sub.16 is alkylene, oxaalkylene or thiaalkylene having in each case 2 to 10 carbon atoms, phenylene or alkenylene having 2 to 6 carbon atoms, Y.sub.17 is alkylene having 2 to 10 carbon atoms, phenylene or alkylphenylene having 1 to 11 carbon atoms in the alkyl moiety, and Y.sub.18 is alkylene having 2 to 10 carbon atoms or alkylene which has 4 to 20 carbon atoms and is interrupted once or several times by oxygen; in formula IV x is an integer from 1 to 3 and the substituents L independently of one another are hydrogen, alkyl, alkoxy or alkylthio having in each case 1 to 22 carbon atoms, phenoxy or phenylthio; and in formula V, Q.sub.1 and Q.sub.2 independently of each other are hydrogen; C.sub.1-C.sub.22alkyl; C.sub.2-C.sub.22 alkenyl, C.sub.2-C.sub.22alkinyl, C.sub.3-C.sub.12cycloalkyl, C.sub.3-C.sub.12cycloalkenyl, C.sub.7-C.sub.20aralkyl, C.sub.1-C.sub.20heteroalkyl, C.sub.3-C.sub.12cycloheteroalkyl, C.sub.5-C.sub.11heteroaralkyl, C.sub.6-C.sub.20aryl, C.sub.4-C.sub.9heteroaryl, COQ.sub.13 or CONQ.sub.13Q.sub.14; Q.sub.3 is CN; COOQ.sub.5; CONHQ.sub.5; COQ.sub.5; SO.sub.2Q.sub.5; CONQ.sub.5Q.sub.6; C.sub.6-C.sub.20aryl; or C.sub.4-C.sub.9 heteroaryl; Q.sub.4 is CN; COOQ.sub.7; CONHQ.sub.7; COQ.sub.7; SO.sub.2Q.sub.7; CONQ.sub.7Q.sub.8; C.sub.1-C.sub.22 alkyl; C.sub.2-C.sub.22alkenyl; C.sub.2-C.sub.22alkinyl; C.sub.3-C.sub.12cycloalkyl; C.sub.3-C.sub.12cycloalkenyl; C.sub.7-C.sub.20aralkyl; C.sub.1-C.sub.20heteroalkyl; C.sub.3-C.sub.12cycloheteroalkyl; C.sub.5-C.sub.11heteroaralkyl; C.sub.6-C.sub.20 aryl; or C.sub.4-C.sub.9 heteroaryl; Q.sub.5, Q.sub.6, Q.sub.7 and Q.sub.8 independently of each other are hydrogen; C.sub.1-C.sub.22alkyl; C.sub.2-C.sub.22alkenyl; C.sub.2-C.sub.22 alkinyl; C.sub.3-C.sub.12cycloalkyl; C.sub.3-C.sub.12cycloalkenyl; C.sub.7-C.sub.20aralkyl; C.sub.1-C.sub.20heteroalkyl, C.sub.3-C.sub.12cycloheteroalkyl; C.sub.5-C.sub.11heteroaralkyl; C.sub.6-C.sub.20aryl; C.sub.4-C.sub.9heteroaryl; SiQ.sub.15Q.sub.16Q.sub.17; Si(OQ.sub.15)(OQ.sub.16)(OQ.sub.17); SiQ.sub.15(OQ.sub.16)(OQ.sub.17); SiQ.sub.15Q.sub.16(OQ.sub.17); or a radical XS; L.sub.1, L.sub.2 or L.sub.3 independently of each other are hydrogen, C.sub.1-C.sub.22alkyl; C.sub.2-C.sub.22alkenyl, C.sub.2-C.sub.22alkinyl; C.sub.3-C.sub.12cycloalkyl; C.sub.3-C.sub.12cycloalkenyl; C.sub.7-C.sub.20aralkyl; C.sub.1-C.sub.20heteroalkyl; C.sub.3-C.sub.12cycloheteroalkyl; C.sub.5-C.sub.11heteroaralkyl; C.sub.6-C.sub.20 aryl; C.sub.4-C.sub.9heteroaryl; CN; OH; OQ.sub.9; or COOQ.sub.9; Q.sub.9 is hydrogen; C.sub.1-C.sub.22alkyl; C.sub.2-C.sub.22alkenyl; C.sub.2-C.sub.22alkinyl; C.sub.3-C.sub.12cycloalkyl; C.sub.3-C.sub.12cycloalkenyl; C.sub.7-C.sub.20aralkyl; C.sub.1-C.sub.20heteroalkyl; C.sub.3-C.sub.12cycloheteroalkyl; C.sub.5-C.sub.11hetero-aralkyl; C.sub.6-C.sub.20 aryl; or C.sub.4-C.sub.9heteroaryl; L.sub.1 and L.sub.2, L.sub.1 and L.sub.3, L.sub.2 and L.sub.3, L.sub.1 and Q.sub.4, L.sub.2 and Q.sub.4, L.sub.1 and Q.sub.1, L.sub.2 and Q.sub.1, L.sub.3 and Q.sub.1, L.sub.3 and Q.sub.5, Q.sub.3 and Q.sub.4, Q.sub.1 and Q.sub.2, Q.sub.7 and Q.sub.8, Q.sub.5 and Q.sub.6 may be linked together to form 1, 2, 3 or 4 carbocyclic or N, O and/or S-heterocyclic rings, which may be further fused with other aromatic rings; Q.sub.10 represents Q.sub.13; COQ.sub.3; COOQ.sub.13; CONH.sub.2; CONHQ.sub.13; or CONQ.sub.13Q.sub.14; Q.sub.11 represents halogen; OH; NH.sub.2; NHQ.sub.15; NQ.sub.15Q.sub.16; NQ.sub.15OQ.sub.16; O-Q.sub.15; OCO-Q.sub.15; S-Q.sub.15; CO-Q.sub.15; oxo; thiono; CN; COOH; CONH.sub.2; COOQ.sub.15; CONHQ.sub.15; CONQ.sub.15Q.sub.16; SO.sub.2NH.sub.2; SO.sub.2NHQ.sub.15; SO.sub.2NQ.sub.15Q.sub.16; SO.sub.2Q.sub.15; SO.sub.3Q.sub.15; SiQ.sub.15Q.sub.16Q.sub.17; SiOQ.sub.15(OQ.sub.16)(OQ.sub.17); SiQ.sub.15(OQ.sub.16)(OQ.sub.17); SiQ.sub.15Q.sub.16(OQ.sub.17); OSi-Q.sub.15Q.sub.16Q.sub.17; OSiOQ.sub.15(OQ.sub.16)(OQ.sub.17); OSi-Q.sub.15Q.sub.16(OQ.sub.17); OSiQ.sub.15(OQ.sub.16)(OQ.sub.17); PO(OQ.sub.15)(OQ.sub.16); or a radical *XS ; Q.sub.12 represents halogen, CN, SH, OH, CHO, Q.sub.18; OQ.sub.18; SQ.sub.18; C(Q.sub.18)=CQ.sub.19Q.sub.20; OCO-Q.sub.19; NHQ.sub.19; NQ.sub.18Q.sub.19; CONH.sub.2; CONHQ.sub.18; CONQ.sub.18Q.sub.19; SO.sub.2NH.sub.2; SO.sub.2NHQ.sub.18; SO.sub.2NQ.sub.18Q.sub.19; SO.sub.2Q.sub.18; COOH; COOQ.sub.18; OCOOQ.sub.18; NHCOQ.sub.18; NQ.sub.18COQ.sub.19; NHCOOQ.sub.19; NQ.sub.19COOQ.sub.20; SiQ.sub.15Q.sub.16Q.sub.17; SiOQ.sub.15(OQ.sub.16)(OQ.sub.17); SiQ.sub.15(OQ.sub.16)(OQ.sub.17); SiQ.sub.15Q.sub.16(OQ.sub.17); OSi Q.sub.15Q.sub.16Q.sub.17; OSiOQ.sub.15(OQ.sub.16)(OQ.sub.17); OSiQ.sub.15Q.sub.16(OQ.sub.17); OSiQ.sub.15(OQ.sub.16)(OQ.sub.17); P(O)OQ.sub.19OQ.sub.20; P(O)Q.sub.19OQ.sub.20; P(O)Q.sub.19Q.sub.20; or a radical XS; or is selected from the group consisting of C.sub.1-C.sub.22alkyl; C.sub.3-C.sub.12cycloalkyl; C.sub.1-C.sub.12alkenyl; C.sub.3-C .sub.12cycloalkenyl; C.sub.1-C.sub.12alkylthio; C.sub.3-C.sub.12cycloalkylthio; C.sub.1-C.sub.12alkenylthio; C.sub.3-C .sub.i2cycloalkenylthio; C.sub.1-C.sub.12alkoxy; C.sub.3-C.sub.12cycloalkoxy; C.sub.1-C.sub.12alkenyloxy; or C.sub.3-C .sub.12cycloalkenyloxy, which may be unsubstituted or substituted by one or more, identical or different Q.sub.11; Q.sub.13, Q.sub.14, Q.sub.15, Q.sub.16, Q.sub.17, Q.sub.18, Q.sub.19 and Q.sub.20 independently of each other are C.sub.1-C.sub.22alkyl; C.sub.3-C.sub.12cycloalkyl; C.sub.2-C.sub.12alkenyl; C.sub.3-C .sub.12cycloalkenyl; C.sub.6-C.sub.14aryl; C.sub.4-C.sub.12heteroaryl; C.sub.7-C.sub.18aralkyl or C.sub.5-C .sub.16heteroaralkyl; or Q.sub.13 and Q.sub.14, Q.sub.15 and Q.sub.16, Q.sub.16 and Q.sub.17 and/or Q.sub.18 and Q.sub.19 may be linked together to form unsubstituted or with C.sub.1-C.sub.4alkyl substituted pyrrolidine, piperidine, piperazine or morpholine; X represents a linker; S signifies a silane-, oligosiloxane- or polysiloxane-moiety; the oligosiloxane is a group of formula Si(Q.sub.15).sub.m[OSi(Q.sub.16)].sub.o wherein m has a value of 0, 1 or2, o has a value of 3, 2 or 1; and m+o have a value of 3 or refers to groups of ##STR00105## wherein A represents a bond to the linker X; and p has a value of 1 to 9; the polysiloxane is a group of ##STR00106## wherein A represents a bond to the linker X; s has a value of 4 to 250; t has a value of 5 to 250; q has a value of 1 to 30; n is 1 or integer; n is from 1 to 6; when n=2, Q.sub.1, Q.sub.5 or Q.sub.4 is a bivalent alkyl group; or Q.sub.1 and Q.sub.2 together with the 2 nitrogen atoms linking them form a unsubstituted or alkyl-substituted ##STR00107## -ring; v is from 1 to 4, w is from 1 to 4; when n=3, Q.sub.1, Q.sub.5 or Q.sub.4 is a trivalent alkyl group; when n=4, Q.sub.1, Q.sub.5 or Q.sub.4 is a tetravalent alkyl group; and Q.sub.1 and Q.sub.2 in formula V are not simultaneously hydrogen.

4. The device of claim 1, wherein the UV absorbing agent is a 2-hydroxybenzophenone derivative selected from the group consisting of a 4-hydroxy, 4-methoxy, 4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, and 2-hydroxy-4,4-dimethoxy derivative of 2-hydroxybenzophenone; a 2-hydroxyphenylbenzotriazole selected from the group consisting of 2-(2-hydroxy-5-methylphenyl)-benzotriazole, 2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole, 2-(5-tert-butyl-2-hydroxyphenyl)benzotriazole, 2-(2-hydroxy-5-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(3,5-di-tert-butyl-2-hydroxyphenyl)-5- chloro-benzotriazole, 2-(3-tert-butyl- 2-hydroxy-5-methylphenyl)-5- chloro-benzotriazole, 2-(3-sec-butyl-5-tert-butyl-2-hydroxypheny)benzotriazole, 2-(2-hydroxy-4-octyloxyphenyl)benzotriazole, 2-(3,5-di-tert-amyl-2-hydroxyphenyl)benzotriazole, 2-(3,5-bis-(alpha,alpha-dimethylbenzyl)-2-hydroxyphenyl)benzotriazole, 2-(3-tert-butyl-2-hydroxy-5-(2-octyloxycarbonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3-tert-butyl-5-[2-(2-ethylhexyloxy)-carbonylethyl]-2-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3-tert-butyl-2-hydroxy-5(2-methoxycarbonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3-tert-butyl-2-hydroxy-5-(2-methoxycarbonylethyl)phenyl)benzotriazole, 2-(3-tert-butyl-2-hydroxy-5-(2-octyloxycarbonylethyl)phenyl)benzotriazole, 2-(3-tert-butyl-5-[2-(2-ethylhexyloxy)carbonylethyl]-2-hydroxyphenyl)benzotriazole, 2-(3-dodecyl-2-hydroxy-5-methylphenyl)benzotriazole, 2-(3-tert-butyl-2-hydroxy-5-(2-isooctyloxycarbonylethyl)phenylbenzotriazole, 2,2-methylene-bis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazole-2-yl-phenol]; a transesterification product of 2-[3-tert-butyl-5-(2-methoxycarbonylethyl)-2-hydroxyphenyl]-2H-benzotriazole with polyethylene glycol 300; ##STR00108## where R=3-tert-butyl-4-hydroxy-5-2H-benzotriazol-2-ylphenyl, 2-[2-hydroxy-3-(alpha,alpha-dimethylbenzyl)-5-(1,1,3,3-tetramethylbutyl)-phenyl]benzotriazole; 5-trifluoromethyl-2-(2-hydroxy-3-alpha-cumyl-5-tert-octylphenyl)-2H-benzotriazole; and 2-[2-hydroxy-3-(1,1,3,3-tetramethylbutyl) -5-(alpha,alpha-dimethylbenzyl)-phenyl]benzotriazole; a 2-hydroxyphenyltriazine selected from the group consisting of 2,4,6-tris(2-hydroxy -4-octyloxyphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-butyloxy-propoxy)phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-octyloxy-propyloxy)phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[4-(3-dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxy-phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxy-propoxy)phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-hexyloxy)phenyl-4,6-diphenyl-1,3,5-triazine, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2, 4,6-tris[2-hydroxy-4-(3-butoxy-2-hydroxy-propoxy)phenyl]-1,3,5-triazine, 2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine, 2-{2-hydroxy-4-[3-(2-ethylhexyl-1-oxy)-2-hydroxypropyloxy]phenyl}-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-(2-ethylhexyl)oxy)phenyl-4,6-di(4-phenyl)phenyl-1,3,5-triazine, 2,4-bis-[(4-(2-ethylhexyloxy)-2-hydroxyphenyl)]-6-(4-methoxyphenyl)-1,3,5-triazine), 2,4-bis-[(4-(2-hydroxyethyloxy)-2-hydroxyphenyl)]-6-(4-chlorophenyl)-1,3,5-triazine), 2,4-bis-(4-butyloxy-2-hydroxyphenyl)-6-(2,4-dibutyloxyphenyl)-1,3,5-triazine), 2-(2-hydroxy-4-[2-ethylhexyloxy]phenyl)-4,6-di(4-phenyl)phenyl-1,3,5-triazine, 2-(2-hydroxy-4-[1-octyloxycarbonyl-ethyl]oxy-phenyl)-4,6-di(4-phenyl)phenyl-1,3,5-triazine, 2,4-bis-(4-[1-octyloxycarbonyl]-ethyloxy-2-hydroxyphenyl)-6-(2,4-dihydroxyphenyl)-1,3,5-triazine), 2,4,6-tris-(4-[1-octyloxycarbonyl]-ethyloxy-2-hydroxyphenyl)-1,3,5-triazine), and 2,4-bis-(4-[1-octyloxycarbonyl]-ethyloxy-2-hydroxyphenyl)-6-(4-[1-octyloxycarbonyl]-ethyloxy-2-hydroxyphenyl)-1,3,5-triazine); or a merocyanine having a formula selected from the group consisting of: ##STR00109## ##STR00110## each including E/Z-isomers thereof.

5. The device of claim 1, wherein the stabilizing agent comprises an antioxidant, which is a compound of formula (1) ##STR00111## wherein G.sub.1 is hydrogen; C.sub.1-C.sub.22alkyl; C.sub.1-C.sub.22alkylthio; C.sub.2-C.sub.22alkylthioalkyl; C.sub.5-C.sub.7cycloalkyl; phenyl; C.sub.7-C.sub.9phenylalkyl; or SO.sub.3M; G.sub.2 is C.sub.1-C.sub.22alkyl; C.sub.5-C.sub.7cycloalkyl; phenyl; or C.sub.7-C.sub.9phenylalkyl; Q is C.sub.mH.sub.2m; ##STR00112## C.sub.mH.sub.2mNH; a radical of formula ##STR00113## T is C.sub.nH.sub.2n; (CH.sub.2).sub.nOCH.sub.2; phenylene; ##STR00114## or a radical of formula (1c) ##STR00115## V is Oor NH; a is 0, 1, or 2; b, c, d and g are each independently of one another 0 or 1; e is an integer from 1 to 4; f is an integer from 1 to 3; and m, n and p are each independently of one another an integer from 1 to 3; q is 0 or an integer from 1 to 3; if e=1, G.sub.3 is hydrogen; C.sub.1-C.sub.22alkyl; C.sub.5-C.sub.7cycloalkyl; C.sub.1-C.sub.22alkylthio; C.sub.2-C.sub.22alkylthioalkyl; C.sub.2-C.sub.18alkenyl; C.sub.1-C.sub.18phenylalkyl; M; SO.sub.3M; a radical of formula ##STR00116## or G.sub.3 is propyl substituted by OH and/or by C.sub.2-C.sub.22alkanoyloxy; M is alkali; ammonium; H; if e=2, then each of b and c independently is 0 or 1; G.sub.3 is a direct bond; CH.sub.2; ##STR00117## or S; or G.sub.3 is propyl substituted by OH or C.sub.2-C.sub.22alkanoyloxy; if e=3, then each of b and c independently is 0 or 1; G.sub.3 is the radical of formula ##STR00118## if e=4, then each of b and c independently is 0 or 1; G.sub.3 is ##STR00119## G.sub.4 are each independently of the other hydrogen; or C1-C22alkyl.

6. The device of claim 1, wherein the stabilizing agent is a compound having formula A or B ##STR00120## wherein R is H or an organic residue, m is 1 or 2, n is 1 or 2, R.sub.1, when n is 1, is hydrogen, alkyl of 1 to 18 carbon atoms, alkenyl of 2-18 carbon atoms, propargyl, glycidyl, alkyl of 2 to 20 carbon atoms interrupted by oxygen and/or substituted by hydroxy, or R.sub.1 is alkyl of 1 to 4 carbon atoms substituted by a carboxy group or by COOZ where Z is hydrogen, alkyl of 1 to 4 carbon atoms or phenyl, when n is 2, R.sub.1 is alkylene of 1 to 12 carbon atoms, alkenylene of 4 to 12 carbon atoms, xylylene, or alkylene of 1 to 20 carbon atoms interrupted by oxygen and/or substituted by hydroxy or phenyl, which phenyl is substituted by hydroxy and/or one to four alkyl groups of 1 to 4 carbon atoms; or R.sub.1 is CO; when m is 1, R.sub.2 is alkyl of 1 to 18 carbon atoms, alkyl of 3 to 18 carbon atoms interrupted by COO, or R.sub.2 is CH.sub.2(OCH.sub.2CH.sub.2).sub.pOCH.sub.3 where p is 1 to 12, or R.sub.2 is cycloalkyl of 5 to 12 carbon atoms, phenyl or said phenyl substituted by one to four alkyl groups of 1 to 4 carbon atoms, or R.sub.2 is NHR.sub.3 where R.sub.3 is alkyl of 1 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenyl or said phenyl substituted by one to four alkyl of 1 to 4 carbon atoms, or R.sub.2 is N(R.sub.3).sub.2 where R.sub.3 is as defined above, and when m is 2, R.sub.2 is a direct bond, alkylene of 1 to 12 carbon atoms, alkenylene of 4 to 12 carbon atoms, O-alkylene-O of 2 to 12 carbon atoms xylylene, alkylene of 2 to 12 carbon atoms interrupted by COO, or R.sub.2 is CH.sub.2(OCH.sub.2CH.sub.2).sub.nOCH.sub.2 where n is 1 to 12, or R.sub.2 is cycloalkylene of 5 to 12 carbon atoms, phenylalkylene of 7 to 15 carbon atoms or phenylene, or R.sub.2 is NHR.sub.4NHwhere R.sub.4 is alkylene of 2 to 18 carbon atoms, cycloalkylene of 5 to 12 carbon atoms, phenylalkylene of 8 to 15 carbon atoms or phenylene, or R.sub.2 is N(R.sub.3)R.sub.4N(R.sub.3)where R.sub.3 and R.sub.4 are as defined above, or R.sub.2 is NH; or the stabilizing agent is selected from the group consisting of: 2,2,6,6-tetramethylpiperidine, 2,2,6,6-tetramethyl-4-hydroxy-piperidine, 2,2,6,6-tetramethyl-4-oxo-piperidine, 1-oxyl-2,2,6,6-tetramethylpiperidine (TEMPO), 1-oxyl-2,2,6,6-tetramethyl-4-hydroxy-piperidine (TEMPOL), bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)succinate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensate of 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, linear or cyclic condensates of N,N-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-tert-octylamino-2,6-dichloro-1,3,5-triazine, tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane-tetracarboxylate, 1,1-(1,2-ethanediyl)-bis(3,3,5,5-tetramethylpiperazinone), 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate, 3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)succinate, linear or cyclic condensates of N,N-bis-(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-morpholino-2,6-dichloro-1,3,5-triazine, the condensate of 2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)ethane, the condensate of 2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazine and 1,2-bis-(3-aminopropylamino)ethane, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, 3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidine-2,5-dione, 3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione, a mixture of 4-hexadecyloxy- and 4-stearyloxy-2,2,6,6-tetramethylpiperidine, a condensation product of N,N-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, a condensation product of 1,2-bis(3-aminopropylamino)ethane and 2,4,6-trichloro-1,3,5-triazine as well as 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No. [136504-96-6]); a condensation product of 1,6-hexanediamine and 2,4,6-trichloro-1,3,5-triazine as well as N,N-dibutylamine and 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No. [192268-64-7]); N-(2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsuccinimide, N-(1,2,2,6,6-pentamethyl -4-piperidyl)-n-dodecylsuccinimide, 2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4,5]decane, a reaction product of 7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro- [4,5]decane and epichlorohydrin, 1,1-bis(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)-2-(4-methoxyphenyl)ethene, N,N-bis-formyl-N,N-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine, a diester of 4-methoxy-methylene-malonic acid with 1,2,2,6,6-pentamethyl-4-hydroxypiperidine, poly[methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4-piperidyl)]siloxane, and a reaction product of maleic acid anhydride--olefin-copolymer with 2,2,6,6-tetramethyl-4-aminopiperidine or 1,2,2,6,6-pentamethyl-4-aminopiperidine.

7. The device of claim 1, wherein the DPP polymer is a polymer comprising a repeating unit of formula ##STR00121## wherein R.sup.1 and R.sup.2 independently are hydrogen, a C.sub.1-C.sub.100alkyl group optionally substituted by one or more halogen atoms, hydroxyl groups, nitro groups, CN, C.sub.6-C.sub.18 aryl groups and/or interrupted by O, COO, OCO, or S; COOC.sub.1-C.sub.50alkyl; a C.sub.7-C.sub.100arylalkyl group; a carbamoyl group; C.sub.5-C.sub.12cycloalkyl which can be substituted one to three times with C.sub.1-C.sub.8alkyl and/or C.sub.1-C.sub.8alkoxy; C.sub.6-C.sub.24aryl, which can be substituted with C.sub.1-C.sub.8alkyl, C.sub.1-C.sub.8thioalkoxy, and/or C.sub.1-C.sub.8alkoxy, or pentafluorophenyl; Ar independently stands for 2,5-thienylene, which may be unsubstituted or substituted by R.sup.3, or for a divalent thiophene or thiazole moiety of the formula ##STR00122## wherein one of X.sup.3 and X.sup.4 is N and the other is CH or CR.sup.3, and R.sup.3 each independently represents C.sub.1-C.sub.25alkyl, which may optionally be interrupted by one or more oxygen atoms.

8. The device according to claim 1, wherein the DPP polymer has a formula (Ia), (Ib), (Ic) or (Id): ##STR00123## wherein x=0.995 to 0.005, y=0.005 to 0.995, and x+y=1; r=0.985 to 0.005, s=0.005 to 0.985, t=0.005 to 0.985, u=0.005 to 0.985, and r+s+t+u=1; n is 4 to 1000, A is a group of formula (X) ##STR00124## wherein a is 1, 2, or 3; a is, 1, 2, or 3; b is 0, 1, 2, or 3; bis, 1, 2, or 3; c is 0, 1, 2, or 3; cis 0, 1, 2, or 3; d is 0, 1, 2, or 3; dis 0, 1, 2, or 3; with the proviso that bis not 0, if a is 0; R.sup.1 and R.sup.2 are the same or different and hydrogen, a C.sub.1-C.sub.100alkyl group, COOR.sup.106, a C.sub.1-C.sub.100alkyl group which is substituted by one or more halogen atoms, hydroxyl groups, nitro groups, CN, or C.sub.6-C.sub.18aryl groups and/or interrupted by O, COO, OCO, or S; a C.sub.7-C.sub.100arylalkyl group, a carbamoyl group, C.sub.5-C.sub.12cycloalkyl, which can be substituted one to three times with C.sub.1-C.sub.8alkyl and/or C.sub.1-C.sub.8alkoxy, a C.sub.6-C.sub.24aryl group, in particular phenyl or 1- or 2-naphthyl which can be substituted one to three times with C.sub.1-C.sub.8alkyl, C.sub.1-C.sub.25thioalkoxy, and/or C.sub.1-C.sub.25alkoxy, or pentafluorophenyl, R.sup.106 is C.sub.1-C.sub.50alkyl; Ar.sup.1, Ar.sup.1, Ar.sup.2, Ar.sup.2, Ar.sup.3, Ar.sup.3, Ar.sup.4 and Ar.sup.4 are independently of each other heteroaromatic, or aromatic rings, which optionally can be condensed and/or substituted, and B, D and E are independently of each other a group of formula ##STR00125## or formula X, with the proviso that in case B, D and E are a group of formula X, they are different from A, wherein k is 1, l is 0, or 1, r is 0, or 1, z is 0, or 1, and Ar.sup.4, Ar.sup.5, Ar.sup.6 and Ar.sup.7 are independently of each other a group of formula ##STR00126## wherein one of X.sup.5 and X.sup.6 is N and the other is CR.sup.14, R.sup.14, R.sup.14, R.sup.17 and R.sup.17 are independently of each other H, or a C.sub.1-C.sub.25alkyl group, which may optionally be interrupted by one or more oxygen atoms.

9. The device of claim 1, wherein the DPP polymer is a polymer comprising a repeating unit of formula
A-D, and at least one repeating unit having a formula B-D, A-E, or B-E, wherein A is a group of formula ##STR00127## ##STR00128## ##STR00129## where R.sup.3 is a C.sub.1-C.sub.18alkyl group, and B, D and E are independently of each other a group of formula ##STR00130## wherein one of X.sup.5 and X.sup.6 is N and the other is CR.sup.14, or CH, R.sup.15, R.sup.15, R.sup.17 and R.sup.17 are independently of each other H, or a C.sub.1-C.sub.25alkyl group, which may optionally be interrupted by one or more oxygen atoms, and R.sup.14 is a C.sub.1-C.sub.25alkyl group, which may optionally be interrupted by one or more oxygen atoms.

10. The device of claim 1, wherein the DPP polymer has a formula of ##STR00131## ##STR00132## ##STR00133## where n is 4 to 1000, R.sup.1 and R.sup.2 are a C.sub.1-C.sub.36alkyl group, R.sup.3 is a C.sub.1-C.sub.18alkyl group, R.sup.15 is a C.sub.4-C.sub.18alkyl group, x=0.995 to 0.005, y=0.005 to 0.995, and x+y=1.

11. The device of claim 1, wherein the stabilizing agent is included in the mixture in the amount of from 0.001 to 0.05 parts by weight per 1 part by weight of the DPP polymer.

12. The device of claim 1, wherein the device comprises the organic field effect transistor comprising the semiconducting layer, and the device further comprises: (a) a source electrode, (b) a drain electrode, (c) a gate electrode, (d) one or more gate insulator layers, and (e) optionally a substrate.

13. A process for producing the organic semiconductor device of claim 1, the process comprising: (aa) mixing the DPP polymer, the stabilizing agent, and a solvent, such that a mixture including 0.0005 to 0.1 parts by weight of the stabilizing agent per 1 part by weight of the DPP polymer is formed; and (bb) applying the mixture onto an electrode, or onto a smoothing layer disposed on the electrode, wherein the electrode is disposed on a substrate.

14. A method for increasing a product life and/or performance of an organic semiconductor device, comprising: including a stabilizing agent selected from the group consisting of a UV absorbing agent, an antioxidant, and an anti-radical agent, into a semiconductor layer comprisinga DPP polymer, such that the semiconductor layer comprises the stabilizing agent in an amount of from 0.0005 to 0.1 parts by weight per 1 part by weight of the DPP polymer.

15. The organic semiconductor device of claim 1, comprising the organic diode.

16. The organic semiconductor device of claim 1, comprising the organic field effect transistor.

17. The organic semiconductor device of claim 1, comprising the organic diode and the organic field effect transistor.

18. A method for protecting the device from degradation by light and/or oxygen during production and/or product life of the device, comprising: including a stabilizing agent selected from the group consisting of a UV absorbing agent, an antioxidant, and an anti-radical agent, into a semiconductor layer comprising a DPP polymer, such that the semiconductor layer comprises the stabilizing agent in an amount of from 0.0005 to 0.1 parts by weight per 1 part by weight of the DPP polymer.

19. The device of claim 3, wherein the stabilizing agent is the UV absorbing agent and is the 2-hydroxyphenyltriazine of formula III.

20. The device of claim 19, wherein the stabilizing agent is included in the mixture in the amount of from 0.001 to 0.05 parts by weight per 1 part by weight of the DPP polymer.

Description

BRIEF DESCRIPTION OF FIGURES

(1) FIG. 1 UV light is irradiated through the PMMA layer (left) in order to mimic the photocrosslinking procedure. Immediately afterwards the gate electrode is evaporated to finalize the OFET-structure (right).

(2) FIG. 2 Typical pristine (filled square) and degraded (open square) transfer characteristics of a) DPP OFETs without additives, b) DPP+1% T780 OFETs, and c) DPP+1% T1577 OFETs. The square-root of the drain currents are also shown for the pristine (filled triangle) and degraded (open triangle) OFETs. The arrows point to the corresponding axes. The curves are swept from V.sub.g=+5 V to 20 V.

(3) FIG. 3 The average field-effect mobility () measured for 24 OFETs of pristine (diamond) and degraded (square) OFETs respectively. are monitored for roughly one month after the photodegradation. The ratio (triangle) and the corresponding trend are also plotted. The estimated error bars are also indicated. Samples containing no stabilizing agent (a), or 1% of Tinuvin 780 (b), Chimassorb 81 (c), Tinuvin 1577 (d).

(4) FIG. 4 The average on-current (i.e., drain-current at the on-state) measured for 24 OFETs of pristine (diamond) and degraded (square) respectively. The on-current values are monitored for roughly one month after the photodegradation. The on-current ratio (triangle) and the trend are also plotted. The estimated error bars are also indicated. Samples containing no stabilizing agent (a), or 1% of Tinuvin 780 (b), Chimassorb 81 (c), Tinuvin 1577 (d).

(5) Where ever mentioned, room temperature denotes a temperature from the range 18-23 C., and percentages are given by weight, unless otherwise indicated.

ABBREVIATIONS

(6) PTFE Polytetrafluoroethylene HALS Hindered Amine Light Stabilizer UVA Ultraviolet light absorber PMMA Poly(methylmethacrylate) OFET Organic field effect transistor DPP Diketopyrrolopyrrole W Transistor channel width L Transistor channel length
Experimental
Preparation of Semiconductor Solutions

(7) The DPP semiconductor according to example 1 of WO10/049321 (see above for details) is blended in anhydrous toluene (>99.5%) to form a stock solution with a concentration of 1.0 wt-%. The solution is heated in oven at 80 C. for two hours. Afterwards the solution is allowed to cool down for one hour before filtering through PTFE-filters with pore diameters 1.0 and 0.45 m.

(8) After the filtration, the stock solution is divided into smaller parts and the additives are distributed accordingly and at concentrations of 0.1 wt-% and 1 wt-% relative to the DPP polymer. Additives used are known compounds (structures shown further below): Tinuvin 780 (T780, a HALS), Tinuvin 120 (T120, a hindered phenolic antioxidant), Tinuvin 1577 (T1577, a hydroxyphenyl triazine class UVA), Chimassorb 81 (C81, a benzophenone class UVA), Tinuvin 312 (T312, an oxanilide class UVA), Tinuvin 326 (T326, a benzotriazole class UVA) and the merocyanine class UVA of CAS-No. 1243654-84-3 (compound MC-03 of WO 09027258).

(9) Fabrication of OFETs

(10) Poly(ethylene terephtalate) (PET) substrates pre-patterned with gold source-drain structures (L=10 m, W/L=1000) are carefully cleaned with acetone and ethanol and afterwards dried on a hotplate at 70 C. for three minutes. DPP polymer (with or without additive) is spin-coated to form a layer thickness of 50 nm. The film is annealed at 90 C. for 30 seconds and afterwards cooled down prior to spin-coating the dielectric. The dielectric is casted from a 4% b.w. solution of poly(methyl methacrylate) (PMMA; molecular weight 950 kD) in butyl acetate. It is spin-coated to form a 500 nm thick dielectric layer and dried for two minutes at 90 C. The devices are finalized by evaporating a 120 nm thick gold-structure to form the gate-electrode. The evaporation is done in vacuum through a shadow mask. The photodegraded devices are fabricated in parallel and with identical process steps. However, after spin-coating of PMMA and before evaporating the gate-electrode, the samples are irradiated with a 1000 W UV-lamp (CONVAC GmbH) for 10 s. All fabrication steps, except for the UV-irradiation, are performed in a clean-room facility.

(11) Degrading and Measuring the OFETs

(12) Photodegradation of the samples is performed using a 1000 W UV-lamp (CONVAC GmbH) before evaporating the gate electrode (FIG. 1). The irradiation is optimized to 10 s in order to cause photodegradation without significantly heating the samples. Two routes are employed for the photodegradation experiments. In one of the routes (Route 1), two samples for each solution are fabricated in parallel; the first sample is kept in darkness while the other sample is irradiated. Hence, more statistical data can be collected at once. Moreover, the established fabrication protocol can be followed without any additional interventions.

(13) In the other route (Route 2), the original sample is cut in half in order to obtain 2 samples containing equal numbers of devices. One of these samples is kept in the dark while the other sample is irradiated. Thus, the comparability between the pristine and the degraded structure is improved, and more samples can be tested at once.

(14) All organic field-effect transistors (OFETs) are measured the next day after fabrication. The devices are stored in the dark and in ambient air before the first measurement and between the measurements. Current-voltage (I-V) characterization is also performed in darkness and in air.

(15) Results: Transfer Characteristics

(16) Tables 1 and 2 show a statistical analysis of reference OFETs (without additive) and of stabilized OFETs (according to the invention). Two different sets of measurements were taken, each using an own reference recorded within the same set. The number of OFETs in each case varies between 10 and 24. The results in tables 1 and 2 show, that the additive effect on the electronic properties is small. The additive influence on the gate (leakage) current is also negligible. Furthermore, there is no systematic trend to the yield of functioning devices. In summary, no significant effect by the stabilizing agent on the device is observed in the absence of photodegradation.

(17) TABLE-US-00002 TABLE 1 Average values for reference OFETs and OFETs containing additive. Conc. I.sub.on .sub.sat Leak On/off Stabilizing Additive [%] [10.sup.4 A] [cm.sup.2/Vs] [10.sup.6 A] [10.sup.4] none (Reference) 0 2.77 0.325 0.715 3.12 Tinuvin 120 0.1 0.93 0.10 0.85 6.9 1 2.05 0.24 0.36 27 Tinuvin 780 0.1 2.87 0.30 1.01 0.8 1 1.39 0.13 0.12 0.8 Tinuvin 234 0.1 1 3.90 0.44 0.24 0.6 Tinuvin 312 0.1 1.04 0.11 1.48 2.2 1 2.25 0.28 6.83 1.3 Tinuvin 326 0.1 1.80 0.21 0.87 5.8 1 1.59 0.19 1.40 7.6 Tinuvin 1577 0.1 2.77 0.32 1.86 7.3 1 0.87 0.10 0.08 5.1 Chimassorb 81 0.1 3.03 0.29 0.48 2.5 1 1.25 0.14 0.07 7.8 .sub.sat is the saturated field-effect mobility. Leak is the gate current at V.sub.d = 20 V. On/off is the on/off ratio between V.sub.d = 0 V and 20 V.

(18) TABLE-US-00003 TABLE 2 Average values for reference OFETs and OFETs having different additives. Conc. I.sub.on .sub.sat Leak On/off Stabilizing Additive [%] [10.sup.4 A] [cm.sup.2/Vs] [10.sup.6 A] [10.sup.4] none (Reference) 0 2.18 0.23 0.71 5.8 Tinuvin 234 0.1 0.61 0.07 0.10 2.7 merocyanine MC-03 0.1 1.56 0.19 0.22 5.8 1 1.02 0.12 0.34 2.5 .sub.sat is the saturated field-effect mobility. Leak is the gate current at V.sub.d = 20 V. On/off is the on/off ratio between V.sub.d = 0 V and 20 V.

(19) FIG. 2 shows typical transfer curves for an OFET without any additives included in the semiconductor (i.e., reference, FIG. 1a) and for two OFETs with 1 wt-% of either the additive T780 (HALS) and T1577 (UVA). Both the pristine (filled square) as well as the photodegraded (open square) devices are shown in each case. The corresponding I.sub.d.sup.1/2-V.sub.g characteristics (filled and open triangle respectively) are also displayed for each transfer curve. In this curve the slope corresponds to the field-effect mobility (). The gate (leakage) currents are generally 0.1% to 1% of the drain current for both the pristine and the photodegraded curves. It can be clearly seen from FIG. 1a) that the UV irradiation results in detrimental effects on the device performance, such as a negative shift in the threshold voltage, a decrease of the on-current and a decline in . These factors imply a worsened charge transport in the active channel, probably caused by the combined effect of UV-light and residual air in the DPP-polymer matrix.

(20) Results shown in FIGS. 2 b) and c) have been obtained with OFETs stabilized 1% of T780 or T1577, respectively. The decrease in the on-current and the decline in (i.e., the slope of (I.sub.d.sup.1/2-V.sub.g) are both smaller than in FIG. 2a). The decline in can be expressed numerically by comparing the values before and after the irradiation. In case of reference sample, the is 28% of the original after irradiation. In case of 1% T780 and 1% T1577, the values for are 53% and 49%, respectively. Similar effects are observed for other stabilizing agents as shown in Table 3.

(21) TABLE-US-00004 TABLE 3 The ratio after/before the UV irradiation using various stabilizers at 1% concentration with DPP-polymer. stabilizer 1% 1% 1% 1% 1% none T780 T326 T312 T324 Ch81 1% T1577 (after)/(before) 0.28 0.53 0.34 0.43 0.33 0.34 0.49

(22) Hence, this is evidence for an immediate stabilizing effect of the respective additive.

(23) Results: Mobility and On-current Kinetics

(24) The I-V characteristics for OFETs with and without the respective additives are monitored regularly for one month. In FIG. 3, the data points represent an average value of 24 OFETs of pristine and photodegraded devices respectively. The reference OFET performance is fairly constant through the course of the study. This is naturally also reflected in the trend of the ratio between the photodegraded and pristine mobility (). For example, in FIG. 3a), falls to just below 20% of the pristine value one day after irradiation. One month later the ratio is just above 20%, i.e., there is hardly any change in either . This indicates that photodegradation of the DPP polymer has an irreversible effect on the device's electronic properties.

(25) Unlike the reference OFETs, all stabilized OFETs in FIG. 3 display an upward trend in the p ratio. This is mainly due to a slight recovery of in the irradiated samples. All stabilized OFETs display a similar effect. The ratio is always higher for the stabilized OFETs than for the reference OFETs, regardless of the identical photodegradation conditions. While the ratio is just below 20% for the reference OFETs, the ratio is about 30% for 1% T780, just below 50% for 1% C81 and above 70% for 1% T1577 blended in the semiconductor.

(26) The on-current for samples of FIG. 3 is shown in FIG. 4. In general, the kinetics is similar to FIG. 3. The recovery effect is larger for the stabilized OFETs than for the reference OFETs. Again also the photodegradation is largest for the reference devices, in which the degraded on-current is about 15% of the pristine value after one day of fabrication. The same ratio is just above 20% for 1% T780, 40% for 1% C81 and 75% for 1% T1577 blended in the semiconductor.

(27) FIGS. 3 and 4 thus show that the additives provide a distinct stabilization of the semiconductor while having very small or no negative impact on the long-term behavior of the OFETs.

(28) Structures/chemical names of the stabilizing agents used:

(29) ##STR00094## ##STR00095##