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Multiphoton Excitation of CsPbBr3 Perovskite Quantum Dots (PQDs): How Many Electrons Can One PQD Donate to Multiple Molecular Acceptors?

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Details

Original languageEnglish
Pages (from-to)2775-2781
Number of pages7
JournalJournal of Physical Chemistry Letters
DOIs
Publication statusPublished - 2019
Publication typeA1 Journal article-refereed

Abstract

Metastable multiexcitonic states (MESs) of semiconductor quantum dots can be involved in multielectron transfer reactions, which opens new perspectives in nanomaterials-based optoelectronic applications. Herein, we demonstrate the generation of a MES in CsPbBr3 perovskite quantum dots (PQDs) and its dissociation dynamics through multiple electron transfers to molecular electron acceptors, anthraquinones (AQs), bound to the PQD surface by a carboxylic anchor. As many as 14 excitons are produced at an excitation density of roughly 220 μJ cm-2 without detectable PQD degradation. Addition of AQ results in the formation of PQD-AQ hybrids with excess of AQs (PQD:AQ ≈ 1:20), which opens the possibility of multielectron transfer acts from MES to AQs. We found that the electron transfer saturates after roughly five transfer acts and that the first electron transfer (ET) time constant is as short as 1 ps. However, each ET increases the Coulomb potential barrier for the next ET, which decreases the rate of ET, resulting in a saturation after five ETs.

Publication forum classification

Field of science, Statistics Finland