Natcore Technology researchers have revealed that the company’s liquid phase deposition (LPD) method could help in the application of an antireflective (AR) coating to planar and textured solar cells resulting in a decrease of wafer thickness by doing away with the thermal vacuum AR coating procedure. The research was done by Natcore scientists at the Columbus-based Ohio State University.
Solar cell developers endeavor to produce cost- effective silicon solar cells by minimizing the wafer thickness from which these cells are fabricated. When the wafer is thin, it cannot completely absorb the light targeted on its surface hence reducing efficiency. Etching the front surface isotropically in an endeavor to form a regular design of pyramids is the method normally employed to solve the problem. The structure of the pyramid faces is so designed that more light gets refracted across multiple angles into the crystal. This makes sure that light does not traverse directly through the cell and gets absorbed partially. This process also called wafer surface texturizing is now widely used in this industry.
After this, the cells are subjected to the typical cell processing stages, one of which is the AR coating procedure and adding contacts. The process of AR coating necessitates that the cells should pass into a vacuum furnace. Since the size of the wafers gets considerably reduced, the AR coating procedure may result in warping of the wafers minimizing production output.
The amount of light reflected from a surface is known as reflectance. The optimal reflectance for solar cells is zero and industry reflectance is 6%. Measurements done at NASA Glenn Research Center in Cleveland, Ohio, reveal that when the wafer is coated with Natcore's LPD antireflective coating, the reflectance level of the texturized wafer gets minimized to less then 2% across the complete absorption band of silicon solar cells.
Source: http://www.natcoresolar.com