| Abstract: | The present disclosure is directed to variable composition ceramics. Zr(2−x)Hf(x)WP2O12 and Hf2WP2O12 exhibit large negative thermal expansion that is linear over a large temperature range up to at least 900° C., These new ceramic material particles may be mixed with polymers to make a composite suitable for use in backsheets for photovoltaic modules or in other applications. The thermal expansion coefficient of the composite can be tailored to match that of the solar cell in order to reduce stress resulting from daily thermal cycling. |