Aggregation-induced emission in lamellar solids of colloidal perovskite quantum wells.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29282451.
- Also identified by DOI 10.1126/sciadv.aaq0208 and PMC identifier 5741399.
- Licence recorded as CC BY-NC.
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Abstract
The outstanding excitonic properties, including photoluminescence quantum yield (η<sub>PL</sub>), of individual, quantum-confined semiconductor nanoparticles are often significantly quenched upon aggregation, representing the main obstacle toward scalable photonic devices. We report aggregation-induced emission phenomena in lamellar solids containing layer-controlled colloidal quantum wells (QWs) of hybrid organic-inorganic lead bromide perovskites, resulting in anomalously high solid-state η<sub>PL</sub> of up to 94%. Upon forming the QW solids, we observe an inverse correlation between exciton lifetime and η<sub>PL</sub>, distinct from that in typical quantum dot solid systems. Our multiscale theoretical analysis reveals that, in a lamellar solid, the collective motion of the surface organic cations is more restricted to orient along the [100] direction, thereby inducing a more direct bandgap that facilitates radiative recombination. Using the QW solids, we demonstrate ultrapure green emission by completely downconverting a blue gallium nitride light-emitting diode at room temperature, with a luminous efficacy higher than 90 lumen W<sup>-1</sup> at 5000 cd m<sup>-2</sup>, which has never been reached in any nanomaterial assemblies by far.