Experimental validation of crystalline silicon solar cells recycling by thermal and chemical methods

In recent years, photovoltaic power generation systems have been gaining unprecedented attention as an environmentally beneficial method for solving the energy problem. From the economic point of view pure silicon, which can be recovered from spent cells, is the most important material owing to its cost and limited supply. The article presents a chemical method for recycling spent or damaged modules and cells, and the results of its experimental validation. The recycling of PV cells consists of two main steps: the separation of cells and their refinement. Cells are first separated thermally or chemically; the separated cells are then refined. During this process the antireflection, metal coating and p-n junction layers are removed in order to recover the silicon base, ready for its next use. This refinement step was performed using an optimised chemical method. Silicon wafers were examined with an environmental scanning electron microscope (ESEM) coupled to an EDX spectrometer. The silicon wafers were used for producing new silicon solar cells, which were then examined and characterized with internal spectral response and current-voltage characteristics. The new cells, despite the fact that they have no SiN(x) antireflective coating, have a very good efficiency of 13-15%. (C) 2010 Elsevier B.V. All rights reserved.