AI Article Synopsis
- The study investigates the relaxation of hot charge carriers in weakly confined hybrid lead iodide perovskite colloidal nanostructures (FAPbI) using advanced femtosecond transient absorption (TA) techniques.
- A new analysis method is introduced that models the temporal evolution of spectral lineshapes, providing a more precise understanding of charge carrier dynamics compared to traditional approaches focusing solely on carrier temperature.
- The research finds that at high excitation levels, cooling times can reach nearly 1 ps due to the hot phonon bottleneck effect and Auger heating, with both phenomena needing simultaneous spectral analysis for effective separation and understanding.
Article Abstract
We study the hot charge carrier relaxation process in weakly confined hybrid lead iodide perovskite colloidal nanostructures, FAPbI (FA = formaminidium), using femtosecond transient absorption (TA). We compare the conventional analysis method based on the extraction of the carrier temperature () by fitting the high-energy tail of the band-edge bleach with a global analysis method modeling the continuous evolution of the spectral lineshape in time using a simple sequential kinetic model. This practical approach results in a more accurate way to determine the charge carrier relaxation dynamics. At high excitation fluence (density of charge carriers above 10 cm), the cooling time increases up to almost 1 ps in thick nanoplates (NPs) and cubic nanocrystals (NCs), indicating the hot phonon bottleneck effect. Furthermore, Auger heating resulting from the multi-charge carrier recombination process slows down the relaxation even further to tens and hundreds of picoseconds. These two processes could only be well disentangled by analyzing simultaneously the spectral lineshape and amplitude evolution.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7598295 | PMC |
| http://dx.doi.org/10.3390/nano10101897 | DOI Listing |
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