Method of manufacture of chalcogenide-based photovoltaic cells

Patent metadata

Field	Value
Publication number	US-9356177-B2
Application number	US-201113096316-A
Country	US
Kind code	B2
Filing date	Apr 28, 2011
Priority date	Apr 30, 2010
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

The invention is a method of forming a cadmium sulfide based buffer on a copper chalcogenide based absorber in making a photovoltaic cell. The buffer is sputtered at relatively high pressures. The resulting cell has good efficiency and according to one embodiment is characterized by a narrow interface between the absorber and buffer layers. The buffer is further characterized according to a second embodiment by a relatively high oxygen content.

First claim

What is claimed is:

1. A photovoltaic cell comprising a backside electrode, a chalcogenide based absorber in contact with the backside electrode, a buffer layer comprising cadmium and sulfur on the absorber, a transparent conductive layer located at the opposite side of the buffer layer from the absorber layer, an electrical collector on the transparent conductive layer, wherein the cell has an interface between the absorber and the buffer layer said interface defined on one side by the point at which the atomic fraction of cadmium exceeds 0.05 in energy dispersive spectroscopy scans of cross section of the cell and defined on a second side by the point at which the atomic fraction of indium and selenium is less than 0.05 and said interface having a thickness of less than 10 nm.

2. The cell of claim 1 wherein the buffer has an average grain size of less than 50 nm.

3. The cell of claim 2 wherein the average grain size is less than 20 nm.

4. The cell of claim 2 wherein the buffer consists essentially of cadmium sulfur, copper and oxygen and the atomic fractions of cadmium and sulfur are at least 0.30.

5. The cell of claim 1 wherein the thickness of the buffer layer is less than 30 nm.

6. The cell of claim 1 wherein cadmium leachate from the cell is less than 1 mg/l.

Assignees

• Bryden Todd R
• Fenton Jr Jeffrey L
• Mitchell Gary E
• Thompson Kirk R
• Mills Michael E
• Parrillo David J
• Dow Global Technologies Llc

Inventors

• Bryden Todd R
• Fenton Jr Jeffrey L
• Mitchell Gary E
• Thompson Kirk R
• Mills Michael E
• Parrillo David J

Classifications

• H10P14/3428

  Sulfides · CPC title

• H10P14/3236

  being chalcogenide semiconducting materials not being oxides, e.g. ternary compounds · CPC title

• H10P14/2923

  being conductive materials, e.g. metallic silicides · CPC title

• H10P14/2901

  Materials · CPC title

• H10P14/22

  using physical deposition, e.g. vacuum deposition or sputtering · CPC title