Black Silicon for Higher Efficiency in Solar Cells

Abstract

The very low efficiency of solar cells can be attributed to a plethora of reasons. The most important reason being, reflection of sunlight from the solar cell surface. Most of the sunlight incident on the solar cells gets reflected back due to the smooth surface of the silicon wafers. This paper presents a novel method to avoid this by using black silicon solar cells. Black silicon tends to make use of the concept of black body radiation to absorb all the rays incident on it and thereby reducing the reflectivity of the solar cell. The nano-fabrication technique involves usage of special wet-etch techniques to achieve nano-sized pores on the surface of silicon. In case of normal solar cells, usually layers of a suitable anti-reflective coating are given which tend to minimize the amount of reflection. This unfortunately increases the manufacturing cost. The unfavourable conditions of heat and dirt further tend to soil the layer of anti-reflective coating, reducing the gains of anti-reflective coating. Thus, black silicon solar cells provide better efficiency while simultaneously reducing the fabrication cost.