In the search for new routes to renewable sources of energy, fabrication of higher –performing, environment-friendly and chemically stable materials is constantly being pursued. Improving the efficiency of utilizing solar energy, the most abundant energy source, is expected to require the design of new photovoltaic materials that can absorb light in the whole UV-visible spectral range. Ferroelectic materials may provide a promising solution.

Ferroelectrics have been attractive in the area of energy storage as they allow for coupling of light absorption with other functional properties. Dr. Andrew Rappe’s work has resulted into a family of single-phase solid oxide solutions that are low-cost, nontoxic, and most importantly, are able to access a wider range of bandgaps from 1.1 to 3.8 electronvolts. This allows these materials to capture a larger percentage of the solar spectrum, and suggest they may be a viable alternative to conventional semiconductor p-n junction solar cells for solar energy conversion.

The invention covers the bandgap engineering strategy wherein two different transition-metal cations located on the perovskite B-site create ferroelectric perovskites with low bandgaps, with one cation driving ferroelectricity and the other giving a bandgap in the visible range. The solid solutions were synthesized by standard solid-state synthesis and synchrotron X-ray diffraction was used to show the formation of a stable perovskite for all the solutions. The study was published in the highly reputed journal Nature and was featured on the cover.

• Ability to capture solar energy 3 to 6 times more than the current state of the art ferroelectric technology
• Can be fabricated using low-cost methods such as sol-gel thin-film deposition and sputtering
• Use of low cost, abundant materials