Thin film photovoltaic device with enhanced light trapping scheme
A thin film photovoltaic device comprising a relief textured transparent cover plate, a layer of transparent conductive oxide having a layer thickness of less than 700 nm, a light absorbing active layer and a reflective back electrode, where the layer of transparent conductive oxide is a non-textured layer.
1. A thin film photovoltaic device comprising:
a relief textured transparent cover plate,
a front electrode consisting of a single layer of transparent conductive oxide having a layer thickness of less than 700 nm,
a light absorbing active layer, and
a reflective back electrode, wherein
the layer of transparent conductive oxide is a non-textured layer, and wherein the transparent cover plate is relief structured by comprising an array of geometrical optical relief structures containing a base, an apex and a set of surfaces, wherein the surfaces connect the base to the apex, and the surfaces are at least three n-polygonal surfaces where n is equal to 4 or higher.
2. The device of claim 1 , wherein the reflective back electrode is non-textured.
3. The device according to claim 1 , wherein the light receiving side of the transparent cover plate is relief textured.
4. The device according to claim 1 , wherein the transparent cover plate is made of a polymeric material.
5. The device according to claim 1 , wherein the relief textured cover plate is applied to a glass plate.
6. The device according to claim 1 , wherein the layer of transparent conductive oxide is made of aluminum doped zinc oxide.
7. The device according to claim 1 , wherein the reflective back electrode is made of silver.
8. The device according to claim 1 , wherein the light absorbing active layer comprises several different layers of absorbing material.
9. The device according to claim 8 , wherein the light absorbing active layer comprises a layer of amorphous silicon and a layer of microcrystalline silicon.