Thin film solar cell structure
First Claim
1. A thin film solar cell structure, comprising:
- at least one non-planar light absorption layer having a first face and a second face opposite to the first face;
a light transmissive first conductive layer arranged on the first face of the light absorption layer; and
a second conductive layer arranged under the second face of the light absorption layer;
wherein the non-planar light absorption layer has peaks and valleys, at least one peak of the non-planar light absorption layer having a first upper portion on the first face and a first lower portion on the second face, at least one valley of the non-planar light absorption layer having a second upper portion on the first face and a second lower portion on the second face, the lower portion of one peak being higher than the upper portion of one valley adjacent to the peak, a vertical distance between the first lower portion of one peak and the second lower portion of one valley adjacent to the peak is at least ten times of a thickness of the light absorption layer, the thickness of the light absorption layer being defined by the distance between the first upper portion and the first lower portion of one peak or the distance between the second upper portion and the second lower portion of one valley, the first conductive layer has uneven undulation substantially along with the light absorption layer;
wherein the non-planar light absorption layer has a relatively flat portion on the second face thereof and the relatively flat portion having slope smaller than 50 degree to a horizontal plane,wherein both the peak and the valley of the non-planar light absorption layer have the relatively flat portion;
wherein a ratio of a total sum of a horizontal projection of the relatively flat portion including in both of the peak and the valley of the non-planar light absorption layer to a horizontal projection of the whole light absorption layer is less than 25%, wherein the horizontal projection is a projected portion to an artificial plane on which a substrate of the thin film solar cell structure is placed;
wherein a series-connecting area between any two neighbor thin film solar cells has a wasted area incapable of generating electrical power, the wasted area having a thickness, a length in the direction of the series connection and perpendicular to the direction of the thickness and an effective width in undulation on a substrate, the thickness of the wasted area being defined by the accumulated thickness of the first conductive layer, the light absorption layer and the second conductive layer at one peak or at one valley.
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Abstract
A thin film solar cell includes a protection layer, a substrate and a photovoltaic conversion structure having a stack of one or several of non-planar light absorption layers, a first conductive layer being light transmissive and a second conductive layer being at least partially transparent or totally reflective. When the second conductive layer is totally reflective, it reflects the sunlight to the adjacent part of the thin film solar cell, proceeding another photovoltaic conversion and generating electric power again. If the non-planar light absorption layer is sloped enough, there will be several photovoltaic conversions produced by the same incident sunlight. More power will be generated and the efficiency of conversion is increased. If the second conductive layer is at least partially transparent, the incident light will be reflected less. However, the structure will provide several opportunities of photovoltaic conversions for the light with larger incident angle.
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Citations
16 Claims
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1. A thin film solar cell structure, comprising:
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at least one non-planar light absorption layer having a first face and a second face opposite to the first face; a light transmissive first conductive layer arranged on the first face of the light absorption layer; and a second conductive layer arranged under the second face of the light absorption layer; wherein the non-planar light absorption layer has peaks and valleys, at least one peak of the non-planar light absorption layer having a first upper portion on the first face and a first lower portion on the second face, at least one valley of the non-planar light absorption layer having a second upper portion on the first face and a second lower portion on the second face, the lower portion of one peak being higher than the upper portion of one valley adjacent to the peak, a vertical distance between the first lower portion of one peak and the second lower portion of one valley adjacent to the peak is at least ten times of a thickness of the light absorption layer, the thickness of the light absorption layer being defined by the distance between the first upper portion and the first lower portion of one peak or the distance between the second upper portion and the second lower portion of one valley, the first conductive layer has uneven undulation substantially along with the light absorption layer; wherein the non-planar light absorption layer has a relatively flat portion on the second face thereof and the relatively flat portion having slope smaller than 50 degree to a horizontal plane, wherein both the peak and the valley of the non-planar light absorption layer have the relatively flat portion; wherein a ratio of a total sum of a horizontal projection of the relatively flat portion including in both of the peak and the valley of the non-planar light absorption layer to a horizontal projection of the whole light absorption layer is less than 25%, wherein the horizontal projection is a projected portion to an artificial plane on which a substrate of the thin film solar cell structure is placed; wherein a series-connecting area between any two neighbor thin film solar cells has a wasted area incapable of generating electrical power, the wasted area having a thickness, a length in the direction of the series connection and perpendicular to the direction of the thickness and an effective width in undulation on a substrate, the thickness of the wasted area being defined by the accumulated thickness of the first conductive layer, the light absorption layer and the second conductive layer at one peak or at one valley. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A thin film solar cell structure, comprising:
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at least one non-planar light absorption layer having a first face and a second face opposite to the first face; a light transmissive first conductive layer arranged on the first face of the light absorption layer; and a second conductive layer arranged under the second face of the light absorption layer; wherein the non-planar light absorption layer has peaks and valleys, at least one peak of the non-planar light absorption layer having a first upper portion on the first face and a first lower portion on the second face, at least one valley of the non-planar light absorption layer having a second upper portion on the first face and a second lower portion on the second face, the lower portion of one peak being higher than the upper portion of one valley adjacent to the peak, a vertical distance between the first lower portion of one peak and the second lower portion of one valley adjacent to the peak is at least ten times of a thickness of the light absorption layer, the thickness of the light absorption layer being defined by the distance between the first upper portion and the first lower portion of one peak or the distance between the second upper portion and the second lower portion of one valley, the first conductive layer has uneven undulation substantially along with the light absorption layer; wherein the non-planar light absorption layer has a relatively flat portion on the second face thereof and the relatively flat portion having slope smaller than 60 degree to a horizontal plane, wherein both the peak and the valley of the non-planar light absorption layer have the relatively flat portion; wherein a ratio of a total sum of a horizontal projection of the relatively flat portion including in both of the peak and the valley of the non-planar light absorption layer to a horizontal projection of the whole light absorption layer is less than 50%, wherein the horizontal projection is a projected portion to an artificial plane on which a substrate of the thin film solar cell structure is placed; wherein a series-connecting area between any two neighbor thin film solar cells has a wasted area incapable of generating electrical power, the wasted area having a thickness, a length in the direction of the series connection and perpendicular to the direction of the thickness and an effective width in undulation on a substrate, the thickness of the wasted area being defined by the accumulated thickness of the first conductive layer, the light absorption layer and the second conductive layer at one peak or at one valley. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification