Superstrate sub-cell voltage-matched multijunction solar cells
AssigneeAlliance for Sustainable Energy, LLC
InventorsAngelo MASCARENHAS, Kirstin ALBERI
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Abstract
Voltage-matched thin film multijunction solar cell and methods of producing cells having upper CdTe pn junction layers formed on a transparent substrate which in the completed device is operatively positioned in a superstate configuration. The solar cell also includes a lower pn junction formed independently of the CdTe pn junction and an insulating layer between CdTe and lower pn junctions. The voltage-matched thin film multijunction solar cells further include a parallel connection between the CdTe pn junction and lower pn junctions to form a two-terminal photonic device. Methods of fabricating devices from independently produced upper CdTe junction layers and lower junction layers are also disclosed.
Claims20
A voltage-matched multijunction solar cell comprising:
- CdTe pn junction layers comprising a CdTe upper sub-cell;
- lower pn junction layers comprising a lower sub-cell;
- and
- a transparent insulating layer positioned between the upper sub-cell CdTe pn junction layers and the lower sub-cell pn junction layers;
- wherein the CdTe upper sub-cell further comprises a transparent superstrate positioned opposite the CdTe pn junction layers from the transparent insulating layer;
- and
- wherein serially connected strings of the CdTe upper sub-cells and serially connected strings of the lower sub-cells, each with substantially equivalent output voltage, are connected in parallel to form a two-terminal voltage matched solar cell.
A method of fabricating a voltage-matched multijunction solar cell comprising:
- providing a transparent substrate having a deposition surface;
- forming a string of serially connected cadmium telluride (CdTe) upper sub-cells on the deposition surface of the superstrate comprising CdTe pn junction layers;
- independently forming a string of serially connected lower sub-cells comprising lower pn junction layers;
- providing a transparent insulating layer between the CdTe pn junction layers, opposite the transparent superstrate, and the lower pn junction layers;
- joining the CdTe pn junction layers and the lower pn junction layers such that the CdTe upper sub-cell is positioned in a superstrate configuration;
- and
- connecting the CdTe upper sub-cell strings and the Si lower sub-cell strings, each with substantially similar output voltage, in parallel to form a two-terminal voltage matched solar cell.
Dependencies are inferred from the claim text.