Solar cells using fullerenes

• US 6,580,027 B2
• Filed: 06/11/2001
• Issued: 06/17/2003
• Est. Priority Date: 06/11/2001
• Status: Expired due to Term

• Current Assignee: The Trustees of Princeton University (Princeton University)
• Original Assignee: The Trustees of Princeton University (Princeton University)
• Inventors: Forrest, Stephen R., Peumans, Peter
• Primary Examiner(s): Diamond, Alan
• Application Number:
  US09/878,523
• Publication Number:
  US 20020189666A1
• Time in Patent Office: 736 Days
• Field of Search: 136/263, 136/256, 136/252, 136/249, 136/255, 136/246, 136/259, 257/40, 257/461, 257/436, 257/431, 250/214.1, 438/82, 438/94, 438/65
• US Class Current: 136/263
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: H01L 31/0256 characterised by the material
• CPC Class Codes: H10K 2102/103 comprising indium oxides, e.g. ITO
• CPC Class Codes: H10K 30/20 comprising organic-organic junctions, e.g. donor-acceptor junctions
• CPC Class Codes: H10K 30/353 comprising blocking layers, e.g. exciton blocking layers
• CPC Class Codes: H10K 39/10 Organic photovoltaic [PV] modules; Arrays of single organic PV cells
• CPC Class Codes: H10K 85/1135 Polyethylene dioxythiophene [PEDOT]; Derivatives thereof
• CPC Class Codes: H10K 85/211 Fullerenes, e.g. C60
• CPC Class Codes: H10K 85/311 Phthalocyanine
• CPC Class Codes: Y02E 10/549 Organic PV cells
• CPC Class Codes: Y10S 977/932 for electronic or optoelectronic application
• CPC Class Codes: Y10S 977/948 Energy storage/generating using nanostructure, e.g. fuel cell, battery

Abstract

Organic photosensitive optoelectronic devices are disclosed. The devises comprise photoconductive organic thin films in a heterostructure, which include an exciton blocking layer to enhance device efficiency. The use of fullerenes in the electron conducting layer has lead to devices with high efficiency. Single heterostructure, stacked and wave-guide type embodiments are disclosed. Devices having multilayer structures and an exciton blocking layer are also disclosed. Guidelines for selection of exciton blocking layers are provided.

Claims

1. An organic photosensitive optoelectronic device comprising:

an anode;

a hole transport layer, the hole transport layer formed of a photoconductive organic semiconductor material;

an electron transport layer over the hole transport layer, the electron transport layer comprising a fullerene;

an exciton blocking layer; and

a cathode,

wherein the device is capable of an external power conversion efficiency of at least about 3.6%.

2. The device of claim 1, wherein the exciton blocking layer is situated between the electron transport layer and the cathode.

3. The device of claim 2, wherein the exciton blocking layer comprises BCP.

4. The device of claim 2, wherein the exciton blocking layer comprises Alq₂OPH.

5. The device of claim 1, further comprising a planarizing layer situated between the hole transport layer and the anode.

6. The device of claim 5, wherein the planarizing layer comprises PEDOT:

PSS.

7. The device of claim 6, wherein the PEDOT:

PSS has been treated with plasma.

8. The device of claim 1, wherein the fullerene is selected from the size range of C₆₀ to C₉₆.

9. The device of claim 1, wherein the fullerene is a nanotube.

10. The device of claim 1, wherein the anode is selected from transparent conducting oxides.

11. The device of claim 10, wherein the anode is ITO.

12. The device of claim 2, wherein:

the electron transport layer is C₆₀,

the hole transport layer is CuPc; and

the exciton blocking layer is BCP.

13. The device of claim 1, wherein the electron transport layer, the hole transport layer, and the exciton blocking layer are disposed between two parallel planar reflective surfaces which form a waveguide.

14. The device of claim 13, having a transparent opening between the two reflective surfaces so that light is admitted to the device from a direction parallel to the planes of the reflective surfaces.

15. A stacked organic photosensitive optoelectronic device comprised of a plurality of photosensitive optoelectronic subcells, wherein at least one subcell includes an electron transporting layer comprising a fullerene, and wherein the device is capable of an external power conversion efficiency of at least about 3.6%.

16. The device of claim 15, wherein the at least one subcell additionally includes an exciton blocking layer and a hole transport layer adjacent the electron transport layer.

17. The device of claim 16, wherein the exciton blocking layer comprises BCP and is adjacent the electron transport layer.

18. The device of claim 16, wherein:

the electron transport layer is C₆₀,

the hole transport layer is CuPc; and

the exciton blocking layer is BCP.

19. A method for making an organic photosensitive optoelectronic device, the device comprising an anode, a hole transport layer, an electron transport layer comprising a fullerene, an exciton blocking layer and a cathode, wherein the device is capable of an external power conversion efficiency of at least about 3.6%, the method comprising the steps of:

(a) depositing the hole transport layer over the anode;

(b) depositing the electron transport layer over the hole transport layer;

(c) depositing the exciton blocking layer over the electron transport layer; and

(d) depositing the cathode over the exciton blocking layer.