Surface plasmon-mediated photoluminescence boost in graphene-covered CsPbBr$_3$ quantum dots
The optical properties of graphene (Gr)-covered CsPbBr$_3$ quantum dots (QDs) were investigated using micro-photoluminescence spectroscopy, revealing a remarkable three-orders-of-magnitude enhancement in photoluminescence (PL) intensity compared to bare CsPbBr$_3$ QDs. To elucidate the underlying me...
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Main Authors | , , , , , , , , |
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Format | Journal Article |
Language | English |
Published |
22.08.2024
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Subjects | |
Online Access | Get full text |
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Summary: | The optical properties of graphene (Gr)-covered CsPbBr$_3$ quantum dots (QDs)
were investigated using micro-photoluminescence spectroscopy, revealing a
remarkable three-orders-of-magnitude enhancement in photoluminescence (PL)
intensity compared to bare CsPbBr$_3$ QDs. To elucidate the underlying
mechanisms, we combined experimental techniques with density functional theory
(DFT) calculations. DFT simulations showed that the graphene layer generates
interfacial electrostatic potential barriers when in contact with the
CsPbBr$_3$ surface, impeding carrier leakage from perovskite to graphene and
enhancing radiative recombination. Additionally, graphene passivates CsPbBr$_3$
surface defect states, suppressing nonradiative recombination of
photo-generated carriers. Our study also revealed that graphene becomes n-doped
upon contact with CsPbBr$_3$ QDs, activating its plasmon mode. This mode
resonantly couples with photo-generated excitons in the perovskite. The
momentum mismatch between graphene plasmons and free-space photons is resolved
through plasmon scattering at Gr/CsPbBr$_3$ interface corrugations,
facilitating the observed super-bright emission. These findings highlight the
critical role of graphene as a top contact in dramatically enhancing CsPbBr$_3$
QDs' PL. Our work advances the understanding of graphene-perovskite interfaces
and opens new avenues for designing high-efficiency optoelectronic devices. The
multifaceted enhancement mechanisms uncovered provide valuable insights for
future research in nanophotonics and materials science, potentially leading to
breakthroughs in light-emitting technologies. |
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DOI: | 10.48550/arxiv.2408.12776 |