US2002176992A1PendingUtilityA1

Highly transparent non-metallic cathodes

42
Priority: Nov 3, 1997Filed: Jul 15, 2002Published: Nov 28, 2002
Est. expiryNov 3, 2017(expired)· nominal 20-yr term from priority
Inventors:Gautam ParthasarathyPaul E. BurrowsStephen R. Forrest
H10K 50/11C07D 487/22H10K 2101/10C09K 2211/185Y10T428/31504C09K 11/06Y10S428/917C09K 2211/186C09K 2211/1029C09K 2211/1074H05B 33/28C09K 2211/1033H10K 2102/3031H10K 50/171H10K 85/631H10K 85/324H10K 71/60H10K 85/371H10K 85/30H10K 2102/3026H10K 50/828H10K 10/82H10K 2102/103H10K 85/311H10K 85/381
42
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Claims

Abstract

A novel class of low reflectivity, high transparency, non-metallic cathodes useful for a wide range of electrically active, transparent organic devices are disclosed. As a representative embodiment, the highly transparent non-metallic cathode of an OLED employs a thin film of copper phthalocyanine (CuPc) capped with a film of low-power, radio-frequency sputtered indium-tin-oxide (ITO). The CuPc prevents damage to the underlying organic layers during the ITO sputtering process. A theory of the invention is presented which suggests that damage-induced states at the non-metallic cathode/organic film interface are responsible for the efficient electron injection properties of the cathode. Due to the low reflectivity of the non-metallic cathode, a non-antireflection-coated, non-metallic-cathode-containing TOLED is disclosed that is 85% transmissive in the visible, emitting nearly identical amounts of light in the forward and back-scattered directions. The performance of the non-metallic-cathode-containing TOLED is found to be comparable to that of TOLEDs employing a more reflective and absorptive cathode consisting of a semi-transparent thin film of Mg:Ag capped with ITO.

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
         1 . A cathode comprising an electrically conductive non-metallic layer in low-resistance electrical contact with a semiconductive organic layer.  
     
     
         2 . The cathode according to  claim 1  wherein the electrically conductive non-metallic layer is comprised of a wide band gap semiconductor having a band gap of at least 1 eV.  
     
     
         3 . The cathode according to  claim 1  wherein the wide band gap semiconductor has a transmission of at least 50% for incident and admitted radiation.  
     
     
         4 . The cathode according to  claim 1  wherein the semiconductive organic layer is comprised of a polyacene compound.  
     
     
         5 . The cathode according to  claim 1  wherein the semiconductive organic layer is comprised of a phthalocyanine.  
     
     
         6 . The cathode according to  claim 1  wherein the semiconductive organic layer is comprised of copper phthalocyanine.  
     
     
         7 . The cathode according to  claim 1  wherein the semiconductive organic layer is comprised of zinc phthalocyanine.  
     
     
         8 . An optoelectronic device comprising a cathode comprised of an electrically conductive non-metallic layer in low-resistance electrical contact with a semiconductive organic layer.  
     
     
         9 . The optoelectronic device according to  claim 8  wherein the electrically conductive non-metallic layer is comprised of a wide band gap semiconductor having a band gap of at least 1 eV.  
     
     
         10 . The optoelectronic device according to  claim 8  wherein the wide band gap semiconductor has a transmission of at least 50% for incident and admitted radiation.  
     
     
         11 . The optoelectronic device according to  claim 8  wherein the semiconductive organic layer is comprised of a polyacene compound.  
     
     
         12 . The optoelectronic device according to  claim 8  wherein the semiconductive organic layer is comprised of a phthalocyanine.  
     
     
         13 . The optoelectronic device according to  claim 8  wherein the semiconductive organic layer is comprised of copper phthalocyanine.  
     
     
         14 . The optoelectronic device according to  claim 8  wherein the semiconductive organic layer is comprised of zinc phthalocyanine.  
     
     
         15 . An organic light emitting device comprising a cathode comprised of an electrically conductive non-metallic layer in low-resistance electrical contact with a semiconductive organic layer.  
     
     
         16 . The organic light emitting device according to  claim 15  wherein the electrically conductive non-metallic layer is comprised of a wide band gap semiconductor having a band gap of at least 1 eV.  
     
     
         17 . The organic light emitting device according to  claim 15  wherein the wide band gap semiconductor has a transmission of at least 50% for incident and admitted radiation.  
     
     
         18 . The organic light emitting device according to  claim 15  wherein the semiconductive organic layer is comprised of a polyacene compound.  
     
     
         19 . The organic light emitting device according to  claim 15  wherein the semiconductive organic layer is comprised of a phthalocyanine.  
     
     
         20 . The organic light emitting device according to  claim 15  wherein the semiconductive organic layer is comprised of copper phthalocyanine.  
     
     
         21 . The organic light emitting device according to  claim 15  wherein the semiconductive organic layer is comprised of zinc phthalocyanine.  
     
     
         22 . An organic laser comprising a cathode comprised of an electrically conductive non-metallic layer in low-resistance electrical contact with a semiconductive organic layer.  
     
     
         23 . The organic laser according to  claim 22  wherein the electrically conductive non-metallic layer is comprised of a wide band gap semiconductor having a band gap of at least 1 eV.  
     
     
         24 . The organic laser according to  claim 22  wherein the wide band gap semiconductor has a transmission of at least 50% for incident and admitted radiation.  
     
     
         25 . The organic laser according to  claim 22  wherein the semiconductive organic layer is comprised of a polyacene compound.  
     
     
         26 . The organic laser according to  claim 22  wherein the semiconductive organic layer is comprised of a phthalocyanine.  
     
     
         27 . The organic laser according to  claim 22  wherein the semiconductive organic layer is comprised of copper phthalocyanine.  
     
     
         28 . The organic laser according to  claim 22  wherein the semiconductive organic layer is comprised of zinc phthalocyanine.  
     
     
         29 . A cathode comprising an electrically conductive non-metallic layer and a semiconductive organic layer wherein the layers are joined by an interface region that lowers the voltage drop across the two layers.  
     
     
         30 . The cathode according to  claim 29  wherein the electrically conductive non-metallic layer is comprised of a wide band gap semiconductor having a band gap of at least 1 eV.  
     
     
         31 . The cathode according to  claim 29  wherein the wide band gap semiconductor has a transmission of at least 50% for incident and admitted radiation.  
     
     
         32 . The cathode according to  claim 29  wherein the semiconductive organic layer is comprised of a polyacene compound.  
     
     
         33 . The cathode according to  claim 29  wherein the semiconductive organic layer is comprised of a phthalocyanine.  
     
     
         34 . The cathode according to  claim 29  wherein the semiconductive organic layer is comprised of copper phthalocyanine.  
     
     
         35 . The cathode according to  claim 29  wherein the semiconductive organic layer is comprised of zinc phthalocyanine.  
     
     
         36 . A method of preparing a cathode for use in an optoelectronic device comprising: 
 depositing an electrically conductive non-metallic layer on an organic layer so as to form an interface region at the surface of the organic layer that lowers the voltage drop across the two layers when the two layers are used as a cathode in an optoelectronic device.    
     
     
         37 . The method according to  claim 36  wherein the electrically conductive non-metallic layer is comprised of a wide band gap semiconductor having a band gap of at least 1 eV.  
     
     
         38 . The method according to  claim 36  wherein the wide band gap semiconductor has a transmission of at least 50% for incident and admitted radiation.  
     
     
         39 . The method according to  claim 36  wherein the semiconductive organic layer is comprised of a polyacene compound.  
     
     
         40 . The method according to  claim 36  wherein the semiconductive organic layer is comprised of a phthalocyanine.  
     
     
         41 . The method according to  claim 36  wherein the semiconductive organic layer is comprised of copper phthalocyanine.  
     
     
         42 . The method according to  claim 36  wherein the semiconductive organic layer is comprised of zinc phthalocyanine.  
     
     
         43 . A method for fabricating a cathode comprising: 
 preparing a cathode comprised of an electrically conductive non-metallic layer and a semiconductive organic layer, wherein the preparation process includes the step of forming an interface region between the electrically conductive non-metallic layer and the semiconductive organic layer, wherein said interface region causes the electrically conductive non-metallic material to be in low-resistance electrical contact with the semiconductive organic layer.    
     
     
         44 . The cathode according to  claim 43  wherein the electrically conductive non-metallic layer is comprised of a wide band gap semiconductor having a band gap of at least 1 eV.  
     
     
         45 . The cathode according to  claim 43  wherein the wide band gap semiconductor has a transmission of at least 50% for incident and admitted radiation.  
     
     
         46 . The cathode according to  claim 43  wherein the semiconductive organic layer is comprised of a polyacene compound.  
     
     
         47 . The cathode according to  claim 43  wherein the semiconductive organic layer is comprised of a phthalocyanine.  
     
     
         48 . The cathode according to  claim 43  wherein the semiconductive organic layer is comprised of copper phthalocyanine.  
     
     
         49 . The cathode according to  claim 43  wherein the semiconductive organic layer is comprised of zinc phthalocyanine.  
     
     
         50 . A display incorporating an optoelectronic device containing the cathode of  claim 1 .  
     
     
         51 . A vehicle incorporating an optoelectronic device containing the cathode of  claim 1 .  
     
     
         52 . A computer incorporating an optoelectronic device containing the cathode of  claim 1 .  
     
     
         53 . A television incorporating an optoelectronic device containing the cathode of  claim 1 .  
     
     
         54 . A printer incorporating an optoelectronic device containing the cathode of  claim 1 .  
     
     
         55 . A wall, theater or stadium screen incorporating an optoelectronic device containing the cathode of  claim 1 .  
     
     
         56 . A billboard or a sign incorporating an optoelectronic device containing the cathode of  claim 1.

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