Fabrication of solar cells with electrically conductive polyimide adhesive
The present disclosure provides a method of manufacturing a solar cell including: providing a first substrate and a second substrate; depositing on the first substrate a sequence of layers of semiconductor material forming a solar cell including a top subcell and a bottom subcell; forming a back metal contact over the bottom subcell; applying a conductive polyimide adhesive to the second substrate; attaching the second substrate on top of the back metal contact; and removing the first substrate to expose the surface of the top subcell.
1. A method of manufacturing a solar cell comprising:
providing a first substrate and a second substrate;
depositing on the first substrate a sequence of layers of semiconductor material forming a solar cell including a top subcell and a bottom subcell;
forming a back metal contact over the bottom subcell;
applying a conductive polyimide adhesive to the second substrate;
attaching the second substrate on top of the back metal contact; and
removing the first substrate to expose the surface of the top subcell.
2. The method of claim 1 . wherein removing the first substrate comprises grinding or lapping.
3. The method of claim 1 wherein the second substrate is a rigid substrate.
4. The method of claim 1 wherein the second substrate is a flexible substrate.
5. The method of claim 1 wherein applying the conductive polyimide adhesive comprises spin coating.
6. The method of claim 1 wherein the conductive polyimide adhesive comprises carbon black particles.
7. The method of claim a 6 wherein the carbon black particles have a size of less than or equal to 5 micrometers.
8. The method of claim 1 wherein the conductive polyimide adhesive comprises silver flakes.
9. The method of claim 1 wherein attaching the second substrate comprises curing the conductive polyimide adhesive at a temperature of from 250° C. to 350° C.
10. The method of claim 9 wherein the cured conductive polyimide adhesive has a resistivity of from 100 Ω-cm to 3000 Ω-cm.
11. A method of manufacturing a metamorphic multijunction solar cell comprising:
providing a first substrate;
depositing on the first substrate a sequence of layers of semiconductor material forming a metamorphic multi junction solar cell including a top subeell and a bottom subcell;
forming a back metal contact over the bottom subcell;
applying a conductive polyimide adhesive to a second substrate;
attaching the second substrate on top of the back metal contact; and
removing the first substrate to expose the surface of the top subcell.
12. The method of claim 11 wherein the back metal contact layer comprises at least one Mo layer.
13. The method of claim 11 wherein the second substrate is a rigid substrate.
14. The method of claim 13 wherein the rigid substrate comprises glass.
15. The method of claim 11 wherein the second substrate is a flexible substrate.
16. The method of claim 15 wherein the flexible substrate comprises a metallic flexible film.
17. The method of claim 11 wherein the conductive polyimide adhesive comprises carbon black particles having a size of less than or equal to 5 micrometers.