Organic EL device and an organic EL device producing method

• US 8,334,647 B2
• Filed: 09/25/2009
• Issued: 12/18/2012
• Est. Priority Date: 03/26/2007
• Status: Active Grant

• Current Assignee: Ulvac Incorporated
• Original Assignee: Ulvac Incorporated
• Inventors: Negishi, Toshio
• Primary Examiner(s): Mai, Anh
• Assistant Examiner(s): LEE, BRENITRA M
• Application Number:
  US12/567,068
• Publication Number:
  US 20100013387A1
• Time in Patent Office: 1,180 Days
• Field of Search: 313/498, 313502-504, 313/506, 445 24- 25, 428/690, 428/917
• US Class Current: 313/504
• CPC Class Codes: H05B 33/22 characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers
• CPC Class Codes: H10K 2102/101 comprising transparent conductive oxides [TCO]
• CPC Class Codes: H10K 2102/103 comprising indium oxides, e.g. ITO
• CPC Class Codes: H10K 50/17 Carrier injection layers
• CPC Class Codes: H10K 50/805 Electrodes
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3

Abstract

A technology is provided, which obtains an organic EL device free from any reduction in the luminescent efficiency, even if an electrode layer is formed on a surface of a charge injection layer by a sputtering method. An organic EL device of the present invention includes a first charge injection layer, a first organic layer, and a second charge injection layer. The second charge injection layer is formed as a mixed layer in which a matrix organic material and a charge injectable metallic material are mixed. Even when the electrode layer is formed on a surface of this second charge injection layer by the sputtering method, the luminescent efficiency does not decrease.

Claims

1. An organic EL device in which charges are injected into a luminescent layer of an organic thin film formed between a first electrode layer and a second electrode layer, thereby emitting a light,

the organic EL device comprising:

a charge injection layer formed between the luminescent layer and the second electrode layer; and

a charge transporting layer formed between the luminescent layer and the charge injection layer,

wherein the charge transporting layer consists of a matrix organic material, the charge injection layer consisting of a thin film in which a charge injectable metallic material and the same matrix organic material as the charge transporting layer are mixed, the charge injectable metallic material is lithium, and a weight ratio of the lithium in the charge injection layer is at least 2%,

wherein the nearer the charge injection layer is to the charge transporting layer, the larger the proportion of the matrix organic material becomes, and

wherein a metallic film formed by a sputtering method is disposed on a surface of the charge injection layer.

2. The organic EL device according to claim 1, wherein the matrix organic material is Alq₃.

3. The organic EL device according to claim 2, wherein the weight ratio of the lithium in the charge injection layer is 2%.

4. The organic EL device according to claim 1, wherein the charge transporting layer is formed by being deposited by a vapor of the matrix organic material alone, and the charge injection layer is formed by being deposited by both a vapor of the matrix organic material and a vapor of the charge injectable metallic material.

5. An organic EL device producing method for producing an organic EL device having a luminescent layer of an organic thin film formed between a first electrode layer and a second electrode layer, a charge injection layer formed between the luminescent layer and the second electrode layer, and a charge transporting layer formed between the luminescent layer and the charge injection layer;

the organic EL device producing method comprising the steps of;

a charge transporting layer forming step in which the charge transporting layer is formed by depositing a vapor of a matrix organic material alone;

a charge injection layer forming step in which the charge injection layer is formed by depositing both the vapor of the matrix organic material and a vapor of the charge injectable metallic material; and

a second electrode layer forming step in which the second electrode layer on a surface of the charge injection layer is formed by a sputtering method,

wherein the charge injectable metallic material of the charge injection layer is lithium, and the weight ratio of the lithium in the charge injection layer is at least 2%, and

wherein, in the charge injection layer forming step, forming the charge injection layer with a higher proportion of the vapor of the matrix organic material than that of the charge injectable metallic material at a start of forming a film and with a higher proportion of the vapor of the charge injectable metallic material than that of the matrix organic material at the later step in the formation of a film in the vapor of the total of the matrix organic material and the charge injectable metallic material.

6. The organic EL device producing method according to claim 5, wherein the matrix organic material is Alq₃.

7. The organic EL device producing method according to claim 6, wherein the weight ratio of the lithium in the charge injection layer is 2%.

8. The organic EL device producing method according to claim 5, wherein generating the vapor of the matrix organic material in the charge transporting layer forming step and the vapor of the matrix organic material in the charge injection layer forming step is from the same vapor deposition source, the vapors being discharged into the same vacuum chamber, thereby forming the charge transporting layer and the charge injection layer in the same vacuum chamber.

9. An organic EL device in which charges are injected into a luminescent layer of an organic thin film formed between a first electrode layer and a second electrode layer, thereby emitting a light,

the organic EL device comprising:

a charge injection layer formed between the luminescent layer and the second electrode layer;

a charge transporting layer formed between the luminescent layer and the charge injection layer; and

an auxiliary charge injection layer formed on the charge transporting layer,

wherein the charge transporting layer consists of a matrix organic material, the charge injection layer consisting of a thin film in which a charge injectable metallic material and the same matrix organic material as the charge transporting layer are mixed, the charge injectable metallic material is lithium,

wherein the nearer the charge injection layer is to the charge transporting layer, the larger the proportion of the matrix organic material becomes,

and

wherein a metallic film formed by a sputtering method is disposed on a surface of the auxiliary charge injection layer, the auxiliary charge injection layer comprising a thin film of the charge injectable metallic material.

10. An organic EL device producing method for producing an organic EL device having a luminescent layer of an organic thin film formed between a first electrode layer and a second electrode layer, a charge injection layer formed between the luminescent layer and the second electrode layer, and a charge transporting layer formed between the luminescent layer and the charge injection layer;

the organic EL device producing method comprising the steps of;

a charge transporting layer forming step in which the charge transporting layer is formed by depositing a vapor of a matrix organic material alone;

a charge injection layer forming step in which the charge injection layer is formed by depositing both the vapor of the matrix organic material and a vapor of the charge injectable metallic material;

an auxiliary charge injection layer forming step in which a thin film of the charge injectable materallic material is formed on the charge injection layer; and

a second electrode layer forming step in which the second electrode layer on a surface of the charge injection layer is formed by a sputtering method,

wherein the charge injectable metallic material of the charge injection layer is lithium, and

wherein, in the charge injection layer forming step, forming the charge injection layer with a higher proportion of the vapor of the matrix organic material than that of the charge injectable metallic material at a start of forming a film and with a higher proportion of the vapor of the charge injectable metallic material than that of the matrix organic material at the later step in the formation of a film in the vapor of the total of the matrix organic material and the charge injectable metallic material.