Resonantly pumped bright-triplet exciton lasing in caesium lead bromide perovskites

The surprising recent observation of highly emissive triplet-states in lead halide perovskites accounts for their orders-of-magnitude brighter optical signals and high quantum efficiencies compared to other semiconductors. This makes them attractive for future optoelectronic applications, especially...

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Bibliographic Details
Published in:arXiv.org 2021-07
Main Authors: Ying, Guanhua, Farrow, Tristan, Atanu Jana, Shao, Hanbo, Im, Hyunsik, Osokin, Vitaly, Seung Bin Baek, Alanazi, Mutibah, Karmakar, Sanjit, Mukherjee, Manas, Park, Youngsin, Taylor, Robert A
Format: Article
Language:English
Subjects:
Cesium
Excitation spectra
Excitons
Lasing
Lead compounds
Metal halides
Nanocrystals
Optical communication
Optical pumping
Optoelectronics
Perovskites
Photoluminescence
Polarizers
Spontaneous emission
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Summary:The surprising recent observation of highly emissive triplet-states in lead halide perovskites accounts for their orders-of-magnitude brighter optical signals and high quantum efficiencies compared to other semiconductors. This makes them attractive for future optoelectronic applications, especially in bright low-threshold nano-lasers. Whilst non-resonantly pumped lasing from all-inorganic lead-halide perovskites is now well-established as an attractive pathway to scalable low-power laser sources for nano-optoelectronics, here we showcase a resonant optical pumping scheme on a fast triplet-state in CsPbBr3 nanocrystals. The scheme allows us to realize a polarized triplet-laser source that dramatically enhances the coherent signal by one order of magnitude whilst suppressing non-coherent contributions. The result is a source with highly attractive technological characteristics including a bright and polarized signal, and a high stimulated-to-spontaneous emission signal contrast that can be filtered to enhance spectral purity. The emission is generated by pumping selectively on a weakly-confined excitonic state with a Bohr radius ~10 nm in the nanocrystals. The exciton fine-structure is revealed by the energy-splitting resulting from confinement in nanocrystals with tetragonal symmetry. We use a linear polarizer to resolve two-fold non-degenerate sub-levels in the triplet exciton and use photoluminescence excitation spectroscopy to determine the energy of the state before pumping it resonantly.
ISSN:2331-8422