Research Seminar of Dr. Yuan Haifeng from KU Leuven

Lecture Time: 09:30 on 30th November, 2017

Lecture Room: B113 of Science and Innovation Building

Lecture Title: Resolving Individual Traps in Perovskite Single Crystals

Yuan Haifeng

KU Leuven

Organic-inorganic halide perovskites (OIHPs) have demonstrated outstanding energy conversion efficiency in solar cells and light emitting devices. In spite of intensive developments in their materials and devices, electronic traps and defects that significantly affect their device properties remain under-investigated. Particularly, it remains challenging to identify and to resolve them individually at the nanoscopic scales. Here, we map non-radiative traps (NRTs) over OIHP nanocrystal morphology of different crystallinity by means of correlative optical super-resolution localization microscopy (SRLM) and electron microscopy. Stochastic and monolithic PL intermittency due to individual NRTs is observed on micron-sized monocrystalline and polycrystalline OIHP nanocrystals. SRLM reveals a heterogeneous PAT distribution across nanocrystals.

Biography

Dr. Haifeng Yuan received his PhD degree at Leiden University in Netherlands in 2013, under the supervision of Prof. Michel Orrit. After that, he joined the group of Prof. Johan Hofkens at Department of Chemistry, KU Leuven in Belgium, where he worked on single-molecule microscopy for resolving light-matter interactions, for instance, plasmonic nanostructures for plasmon-enhanced spectroscopy, photophysical and photochemical processes in perovskites and photocatalysis. In 2017, he joined the group of Prof. Ted Sargent as a postdoctoral fellow to work with perovskite optoelectronic devices. He is now a FWO postdoctoral fellow at KU Leuven, Belgium. He has authored and co-authored 20+ SCI articles in high-impact journals of Angewandte Chemie, ACS Nano, Journal of Physical Chemistry Letters, etc.