Lecture by prof. Ivana G. Scheblykina from Lund University

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Academic Centre for Materials and Nanotechnology invites for a seminary that will be held on 19^th January, 2017, at 2 pm.

 

A lecture titled “Luminescence super-resolution microscopy of organo-metal halide perovskite semiconductors: the role of defects and nano-morphology on electron dynamics” will be given by prof. Ivana G. Scheblykina from Lund University in Sweden.

 

Venue: Kawiory 30 Street, building D-16, room on 2^nd floor

An abstract of the lecture

Organo-metal halide perovskites are very promising materials for new generations of low-cost solar cells and light-emitting devices. Their solution processability is a beneficial feature, although it leads to a great spatial inhomogeneity of films, spatial variation of the trap state density and a great sensitivity of the properties to the environment. Due to the sample inhomogeneity, unraveling the fundamental physical processes by traditional spectroscopy methods is difficult, calling for their combination with microscopy techniques in order to see beyond the ensemble-averaged response. In my talk I will show how fluorescence microscopy and single molecule spectroscopy approaches can be employed to study this interesting material. Among several, I will discuss such a fascinating phenomenon as luminescence blinking of individual nano- and even micro crystals of methylammonium lead iodide. Luminescence blinking reports on efficient charge migration over the crystal volume and the ability of just one trapping state to control the fate of all photoexcited charge carriers in the whole volume of the microcrystal. The nature of such ”super-trap” is not known, we speculate that it might be is a donor-acceptor complex formed by a hole and electron trap located in close spatial proximity able to immobilize diffusing charges resulting in efficient non-radiative recombination. The super-trap can be temporarily passivated by interaction with slowly migrating species like ions or impurities.

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