Ultralow Threshold Room Temperature Polariton Condensation in Colloidal CdSe/CdS Core/Shell Nanoplatelets

Yang, Hong-Chang; Zhang, Lei; Xiang, Wenbin; Lü, Changgui; Cui, Yiping; Zhang, Jiayu

doi:10.1002/advs.202200395

Cited by 13 publications

(8 citation statements)

References 45 publications

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“…Notably, the threshold fluence P th = 6.0 μJ/cm 2 is very low; compared to photon lasing using core-only CdSe NPLs ( P th ≈ 150–200 μJ/cm 2 ), , this threshold is around 25-fold less. Despite higher optical losses intrinsic to plasmonic cavities, this low threshold is similar to dielectric-cavity lasers that integrate gain-engineered materials such as core/crown CdSe NPLs or lead halide perovskite nanocrystals. − …”

Section: Results and Discussionmentioning

confidence: 96%

Room-Temperature Polariton Lasing from CdSe Core-Only Nanoplatelets

Freire-Fernández,

Sinai,

Hui Tan

et al. 2024

ACS Nano

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This paper reports how CdSe core-only nanoplatelets (NPLs) coupled with plasmonic Al nanoparticle lattices can exhibit exciton-polariton lasing. By improving a procedure to synthesize monodisperse 4-monolayer CdSe NPLs, we could resolve polariton decay dynamics and pathways. Experiment and theory confirmed that the system is in the strong coupling regime based on anticrossings in the dispersion diagrams and magnitude of the Rabi-splitting values. Notably, polariton lasing is observed only for cavity lattice periodicities that exhibit specific dispersive characteristics that enable polariton accumulation. The threshold of polariton lasing is 25-fold lower than the reported photon lasing values from CdSe NPLs in similar cavity designs. This open-cavity platform offers a simple approach to control exciton polaritons anticipated to benefit quantum information processing, optoelectronics, and chemical reactions.

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Section: Results and Discussionmentioning

confidence: 96%

Room-Temperature Polariton Lasing from CdSe Core-Only Nanoplatelets

Freire-Fernández,

Sinai,

Hui Tan

et al. 2024

ACS Nano

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“…CdSe NPLs have been recently explored in various exciton-polaritonic systems (43)(44)(45)(46) due to their well-defined narrow absorption and photoluminescence (PL) linewidths (~40 meV), high oscillator strengths, and small Stokes shifts (~5-10 meV), making them excellent materials for achieving and investigating strong light-matter coupling (47)(48)(49)(50). Here, we integrated 4.5 monolayer CdSe NPLs (approximate lateral size of 22 nm x 15 nm, see SI Appendix for fabrication details) into two types of FP microcavities with varying cavity Q-factors as illustrated in Fig.…”

Section: Polariton Dispersion Characteristicsmentioning

confidence: 99%

Cavity Controlled Upconversion in CdSe Nanoplatelet Polaritons

Amin,

Koessler,

Morshed

et al. 2024

Preprint

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Strong coupling between electronic transitions of matter and confined electromagnetic fields inside an optical cavity creates hybrid, light-matter states known as polaritons. Polaritons provide a versatile platform for investigating quantum electrodynamics effects in chemical systems, such as polariton-altered chemical reactivity. However, using polaritons in chemical contexts will require a better understanding of the photophysical properties of polaritons, especially at ambient temperature and pressure, where chemistry is typically performed. Here, we investigated leveraging strong light-matter interactions to control the excited state dynamics of colloidal CdSe nanoplatelets (NPLs) coupled to a Fabry-Pérot optical cavity. Importantly, changes in the cavity quality (Q) factor, which is a measure of photon loss from the cavity, were used to profoundly change the polariton dynamics. As the Q-factor was increased, we observed significant population of the upper polariton (UP) state, exemplified by the rare observation of substantial UP photoluminescence (PL) at room temperature. In fact, with low energy excitation at the lower polariton (LP), which is not absorbed by uncoupled nanoplatelets, we observed upconverted PL emission from the UP branch, due to efficient exchange of population between the LP, UP and the reservoir of dark states present in collectively coupled polaritonic systems. Critical physical insight into the mechanism of PL enhancement of the UP, and PL upconversion, was provided by state-of-the-art quantum dynamics simulations that account for multiple cavity electromagnetic modes and cavity loss. In addition, by resolving lower and upper polariton PL lifetimes, we found timescales for polariton dynamics on the order of 100 picoseconds, implying great potential for NPL based polariton systems to affect photochemical reaction rates. This work provides important insight into the photophysics of nanocrystal-based exciton-polariton systems and is a significant step towards the development of practical polariton photochemistry platforms.

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“…[37,38] Since the first report on quantum-sized 2D CdSe nanoribbons, [23] synthesis protocols have expanded to encompass other 2D semiconductors, such as CdS, [24] CdTe, [25,39,40] ZnSe, [41] ZnS, [22] CuS, [22] PbS, [26] perovskite, [42,43] and their heterostructures. [31][32][33][34][35]44] They are designated according to their lateral shapes, such as nanoribbons, [23] nanosheets, [25] nanoplatelets, [45] nanohelices, [46] quantum disks, [47] or quantum nets. [48] Considering the crystal structures of II-VI semiconductor materials, i.e., cubic zincblende and hexagonal wurtzite, the formation of 2D nanocrystals are inherently challenging, [49][50][51] suggesting that comprehensive understanding of their formation mechanism is required.…”

Section: Introductionmentioning

confidence: 99%

Revealing Two Distinct Formation Pathways of 2D Wurtzite‐CdSe Nanocrystals Using In Situ X‐Ray Scattering

Lee,

Bootharaju,

Lee

et al. 2023

Advanced Science

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Understanding the mechanism underlying the formation of quantum‐sized semiconductor nanocrystals is crucial for controlling their synthesis for a wide array of applications. However, most studies of 2D CdSe nanocrystals have relied predominantly on ex situ analyses, obscuring key intermediate stages and raising fundamental questions regarding their lateral shapes. Herein, the formation pathways of two distinct quantum‐sized 2D wurtzite‐CdSe nanocrystals — nanoribbons and nanosheets — by employing a comprehensive approach, combining in situ small‐angle X‐ray scattering techniques with various ex situ characterization methods is studied. Although both nanostructures share the same thickness of ≈1.4 nm, they display contrasting lateral dimensions. The findings reveal the pivotal role of Se precursor reactivity in determining two distinct synthesis pathways. Specifically, highly reactive precursors promote the formation of the nanocluster‐lamellar assemblies, leading to the synthesis of 2D nanoribbons with elongated shapes. In contrast, mild precursors produce nanosheets from a tiny seed of 2D nuclei, and the lateral growth is regulated by chloride ions, rather than relying on nanocluster‐lamellar assemblies or Cd(halide)2–alkylamine templates, resulting in 2D nanocrystals with relatively shorter lengths. These findings significantly advance the understanding of the growth mechanism governing quantum‐sized 2D semiconductor nanocrystals and offer valuable guidelines for their rational synthesis.

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Ultralow Threshold Room Temperature Polariton Condensation in Colloidal CdSe/CdS Core/Shell Nanoplatelets

Cited by 13 publications

References 45 publications

Room-Temperature Polariton Lasing from CdSe Core-Only Nanoplatelets

Room-Temperature Polariton Lasing from CdSe Core-Only Nanoplatelets

Cavity Controlled Upconversion in CdSe Nanoplatelet Polaritons

Revealing Two Distinct Formation Pathways of 2D Wurtzite‐CdSe Nanocrystals Using In Situ X‐Ray Scattering

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