Green, lead-free solar cell technology The French firm Metalor has discovered how to remove lead from the process of making solar cells without compromising the quality of the end product. Climate Change and Environment © Shutterstock While power generation from renewable solar energy is environmentally friendly, the production of photovoltaic panels is not. Lead features prominently in the creation of crystalline silicon solar cells. Unfortunately, lead is an extremely toxic heavy metal that can cause severe damage to the human nervous system. The EC2 CONTACT project was founded with the aim of making solar technology as green as possible while at the same time achieving substantial cost reductions. Metalor, an EC2 CONTACT partner from France, was called upon to develop lead-free alternatives to replace traditional leaded metallisation pastes. Further to extensive research, Metalor substituted glass frit and binder for lead in the new pastes. Silver (Ag) and aluminium (Al) pastes created for the new technique demonstrated performance characteristics on a par with those of their lead counterparts. In particular, fill factors and efficiencies were in the order of 77% and 17% respectively. Additional benefits were also detected. For instance, the resulting silicon nitride (SiNx) cells exhibited greater resistance to bowing. Metalor and its EC2 CONTACT partners plan to promote the new technology to the rapidly expanding market for green products.
