Dr. Tomas LEIJTENS

Dr. Tomas LEIJTENS

Researcher
Stanford University, United States

While perovskites have already reached single junction power conversion efficiencies over 22 %, their tunable bandgap means that they are ideal candidates for tandem solar cells to push PV efficiencies past 30 % at low costs. This presentation will discuss the great possibilities that perovskites provide in terms of making perovskite – silicon as well as perovskite-perovskite tandem solar cells. Our work at Stanford shows that it is possible to combine a planar heterojunction perovskite solar cell with a heterojunction silicon solar cell to make a 23.6 % monolithic tandem. We have also developed an efficient small (1.2 eV) bandgap perovskite which we can pair with a wider gap perovskite to make current matched monolithic tandems of 17 %, and mechanically stacked tandems exceeding 20 %.  The stability of the materials is also investigated and is found to be surprisingly good; the solar cells can readily meet the IEC criteria. 

Biography

Dr. Tomas Leijtens obtained his PhD in 2014 under supervision of Prof Henry J Snaith, working to understand charge transport mechanisms and stability of dye sensitized and metal halide perovskite solar cells. From 2013-2015 he was a Marie Curie (ITN) fellow at the Center for Nano Science and Technology in Milan, where he investigated photophysical processes and degradation in metal halide perovskite semiconductors under supervision of Dr. Annamaria Petrozza. He is currently a postdoctoral researcher at Stanford University working with Prof Michael McGehee and holds a postdoctoral Marie Curie Fellowship (IOF). His current research is focused on the development of small bandgap perovskite absorbers and their use in all-perovskite tandem solar cells.