October 25, 2019 @ 1:30 pm – 2:30 pm
host: Laszlo Mihaly
title: Why are hybrid halide perovskites exciting materials?
Laboratory of Physics of Complex Matter
Ecole Polytechnique Fédérale de Lausanne
Recently, it has been shown that CH3NH3PbI3 is very promising material in photovoltaic devices1 reaching light conversion efficiency (η) up to 22%2. A strong research activity has been focused on the chemistry of the material to establish the most important parameters which could further improve η and to collect photons from a broad energy window. The major trend in this field is in photovoltaic device engineering although the fundamental aspects of the material are not yet understood.
In my lab we have devoted considerable effort to the growth of high quality single crystals at different length scales, ranging from large bulk crystals (up to 100 mm3) through nanowires3,4 down to quantum dots of tens of nanometers of linear dimensions. The structural tunability of the material allows to study a broad range of physical phenomena including electrical and thermal transport, magnetism, optical properties, band structure by photoemission etc. With a selected set of measurements I will demonstrate our enthusiasm for this material both in basic science and in device applications5,6.
Acknowledgement: The work has been performed in collaboration with Endre Horvath, Massimo Spina, Balint Nafradi, Peter Szirmai, Alla Araktcheva, Andrea Pisoni, Jacim Jacimovic, Andrzej Sienkiewicz, Claudio Grimaldi, Hugo Dil, Henrik Ronnow and many others.
1. Lee, M. M. et al.,Science 338, 643-647 (2012).
2. see reports of the Gaetzel and Hagfeldt groups
3. Horvath et al., Nano Letters 14, 6761, (2015)
4.Spina et al., (2016) Scientific Reports, 6, 1
5.Spina et al., (2015) Small, 11, 4823 ; Spina et al., Nanoscale, 2016, 8, 4888
6.Nafradi et al., J. Phys. Chem. C 2015, 119, 25204