Life cycle assessment of thin film non conventional photovoltaics: The case of dye sensitized solar cells

Abstract

Energy lies at the heart of any nation's technological, economical and social development. In recent years, energy demand has grown constantly and is bound to further increase. In this context, the interest of the scientific community is progressively moving towards renewable energy sources, with a particular focus on developing the technologies necessary for their exploitation, and towards sustainable growth. The search for alternative energy sources, able to combine efficiency, ease of use and reduced environmental impact is therefore, together with energy saving, an important challenge for our civilization. Among the various renewable energy sources available on our planet, solar energy is particularly attractive. One of the technologies available to produce electricity from solar energy is photovoltaics. With the aim of achieving a larger distribution of photovoltaics, research turned itself to the development of new technologies based on alternative materials, such as organic compounds. Some of these technologies exploit the capacity of organic dyes to liberate electrons as in natural photosynthesis. To this category belong the solar cells known as dye sensitized solar cells (DSSC), also known as Grätzel-type cells (Nature 1991). Such cells have attracted much interest, especially in the last decade, because of their potentially low cost of production. Thanks to the employment of readily available materials, produced by well-established processes, they actually present drastically lower economic and environmental costs compared with traditional silicon-based cells even though they are not efficient enough yet to be industrially competitive. An emerging challenge is to find the right set of materials to obtain DSSC of improved performances. Progress in this field requires major investments in terms of research and development aimed at the optimization of all parameters. In this study we present the preliminary results of life cycle assessment for the production of a DSSC. These results have been obtained through a multidisciplinary project for the design and synthesis of new organic sensitizers for DSSC. The life cycle assessment has been developed based on actual production data along all the project stages in order to evaluate the environmental impacts and the energy consumption associated with the production process. This analysis will be pivotal in understanding the environmental dynamics, the benefits and drawbacks associated with the production of DSSC in comparison with other photovoltaic technologies.