Speaker
Alex Koegel
Speaker's Institution
Colorado State University
Date
10/19/18
Time
4:00 PM
Location
Chemistry A101
Mixer Time
3:45 PM
Mixer Location
Chemistry B101E
Additional Information

Literature Seminar Abstract:

Charge dynamics in materials such as recombination lifetimes and mobility are fundamental in understanding the way devices work. A family of hybrid halide perovskites with the formula A’2An-1BnX3n+1 (where A’ = RNH3+, A = CH3NH3+, B = divalent metal center, X = halide, and n is an integer) are of interest for their white-light emission with applications in solid-state lighting. This emission is thought to arise from excitons – a coulombically bound electron hole pair – separating into free charges. Charge dynamics, specifically excitonic dissociation, is not well understood in these materials. A recent report by Gélvez-Rueda and coworkers studies the effect of temperature and dimensionality on excitonic dissociation in a system of layered lead-iodide perovskites using a combination of microwave conductivity measurements. They determine exciton dissociation and formation of free charges are inversely proportional by measuring the mobility of free charges through the layered perovskites. This work shows direct experimental evidence for the formation of free carriers upon excitonic dissociation.

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