Tracking convoluted charge carrier and defect dynamics in luminescent semiconductors
Ivan Scheblykin a
a Chemical Physics and NanoLund, Department of Chemistry, Lund University, Box 124, Lund 22100, Sweden
Proceedings of Neuronics Conference (Neuronics)
València, Spain, 2024 February 21st - 23rd
Organizers: Sabina Spiga and Juan Bisquert
Invited Speaker, Ivan Scheblykin, presentation 009
Publication date: 18th December 2023

Optoelectronic memristors open new opportunities for neurosynaptic devices and optoelectronic systems.[1] The phenomenon of photoluminescence present in many semiconductors gives us a possibility to learn about charge recombination using rather simple optical spectroscopy methods. In this talk, I will describe a novel technique of automotive mapping of photoluminescence quantum yield leading to a PLQY (f,P) map, which is also called a “Horse map”.[2,3] This map presents PLQY of a material in the space of the laser pulse energy (P) and the laser repletion rate (f) where the scanning of P and f occurs over many orders of magnitude in a pre-designed programmable manner.

The “Horse map” is a fingerprint of both charge carrier dynamics occurring at timescales from nanoseconds to microseconds and of the defect dynamics happening at time scales from milliseconds to hours. For the latter the automatization of the mapping is crucial since the defect evolution occurs during the experiment itself.[3] It means that the methodology is applicable for materials which change their properties over time, like, for example, a material of memristor under repetitive writing/reading cycles.

I will further unveil how PLQY(f,P) mapping allows to extract the concentration of defect states and their nature. I will describe the so called “observer effect” in metal-halide perovskites which is the consequence of the defect dynamics.[3]

I envision that further development of PLQY mapping over a multi-parameter space not limited to f and P, for example using hybrid optoelectrical stimuli, will be desired for the optoelectronic memristor community to rationalize charge carrier dynamics under real device operation conditions.


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