Spatially-doped charge transport layers
View Patent ↗Disclosed herein is an organic electronic device comprising a charge transport layer comprising a host charge transport material and a guest charge transport material, wherein the guest material is not homogeneously distributed in the host material and is spatially doped within the host material. The charge transport layer may be either a hole or electron transport layer and is useful in a variety of organic electronic devices.
1. An organic electronic device comprising a charge transport layer comprising a host charge transport material and a guest charge transport material, wherein said guest material is not homogeneously distributed in the host material and is spatially doped within the host material.
2. A device according to claim 1 , wherein the host material is a hole transport material and the guest material is a hole transport material.
3. A device according to claim 2 , wherein the lowest unoccupied molecular orbital level of the guest hole transport material is higher than the lowest unoccupied molecular orbital level of the host hole transport material.
4. A device according to claim 2 , wherein the host material is different from the guest material, and each of the host material and guest material is selected from N,N′-diphenyl-N,N′-bis(3-methylphenyl)-[1,1′-biphenyl]-4,4′-diamine (TPD), 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), N,N′-bis(4-methylphenyl)-N,N′-bis(4-ethylphenyl)-[1,1′-(3,3′-dimethyl)biphenyl]-4,4′-diamine (ETPD), tetrakis-(3-methylphenyl)-N,N,N′,N′-2,5-phenylenediamine (PDA), a -phenyl-4-N,N-diphenylaminostyrene (TPS), p-(diethylamino)benzaldehyde diphenylhydrazone (DEH), triphenylamine (TPA), bis[4-(N,N-diethylamino)-2-methylphenyl](4-methylphenyl)methane (MPMP), 1-phenyl-3-[p-(diethylamino)styryl]-5-[p -(diethylamino)phenyl]pyrazoline (PPR or DEASP), 1,2-trans-bis(9H-carbazol-9-yl)cyclobutane (DCZB), N,N,N′,N′-tetrakis(4-methylphenyl)-(1,1′-biphenyl) 4,4′-diamine (TTB), 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB or NPD), carbazole biphenyl (CBP), porphyrinic compounds, polyvinylcarbazole, (phenylmethyl)polysilane, polythiophenes, polypyrroles, polyanilines and mixtures thereof.
5. A device according to claim 1 , wherein the host material is an electron transport material and the guest material is an electron transport material.
6. A device according to claim 5 , wherein the highest occupied molecular orbital level of the guest electron transport material is lower than the highest occupied molecular orbital level of the host electron transport material.
7. A device according to claim 2 , wherein the host material comprises a compound having at least two carbazole groups and the guest material comprises a triarylmethane compound.
8. A device according to claim 2 , wherein the host material comprises Formula I below:
wherein E is selected from a single bond, (CR 1 R 2 ) m , O, S, (SiR 1 R 2 ) m wherein m is an integer of 1 to 20, wherein R 1 and R 2 are each independently selected from H, F, alkyl, aryl, alkoxy, aryloxy, fluoroalkyl, fluoroaryl, fluoroalkoxy, and fluoroaryloxy, and wherein R 1 and R 2 can, when taken together, form 5- or 6-membered rings;
and wherein the guest hole transport material comprises Formula II below:
wherein:
Ar 1 can be the same or different at each occurrence and is selected from aryl and heteroaryl;
R 3 can be the same or different at each occurrence and is selected from H, alkyl, heteroalkyl, aryl, heteroaryl, arylalkylene, heteroarylalkylene, C n H a F b , and C 6 H c F d ; or adjacent R 3 groups can be joined to form 5- or 6-membered rings;
X can be the same or different at each occurrence and is selected from R 3 , alkenyl, alkynyl, N(R 1 ) 2 , OR 1 , OC n H a F b , OC 6 H c F d , halide, NO 2 , OH, CN, and COOR 1 ;
n is an integer, and
a, b, c, and d are 0 or an integer such that a+b=2n+1, and c+d=5.
9. A device according to claim 2 , wherein the host is CBP and the guest is MPMP.
10. A device according to claim 5 , wherein the host material is different from the guest material, and each of the host material and guest material is selected from metal chelated oxinoid compounds, azole compounds, quinoxaline derivatives, phenanthroline derivatives, and mixtures thereof.
11. A device according to claim 1 , wherein the device is selected from a light-emitting diode, a light-emitting diode display, a laser diode, a photodetector, photoconductive cell, photoresistor, photoswitch, phototransistor, phototube, IR-detector, photovoltaic device, solar cell, light sensor, photoconductor, electrophotographic device, transistor, or diode.
12. A device according to claim 1 , wherein the guest material is present as an ultrathin sublayer within the host material.
13. A device according to claim 1 , wherein the guest material is present in discrete locations within the host material.
14. A device according to claim 1 , wherein the host material is at least 60% by weight of the charge transport layer.
15. A device according to claim 1 , wherein the host material is at least 75% by weight of the charge transport layer.
16. A device according to claim 1 , wherein the charge transport layer has a first thickness and the guest material comprises a thin film having a second thickness within the host material, and the second thickness is less than 50% of the first thickness.
17. A device according to claim 16 , wherein the second thickness is from 1% to 20% of the first thickness.