Inverse size-dependent Stokes shift in strongly quantum confined CsPbBr<sub>3</sub> perovskite nanoplates

Vurgaft, A. V.; Strassberg, Rotem; Shechter, Reut; Lifer, Rachel; Dahl, Jakob; Chan, Emory M.; Bekenstein, Yehonadav

doi:10.1039/d2nr03275a

Cited by 7 publications

(12 citation statements)

References 57 publications

(97 reference statements)

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“…The PL maximum of NRs and NWs is located at 460 nm, while for the NCs it is at 470 nm. The stock shift of NRs and NWs is rather low, which is mainly due to the 2D confined excitons in such systems . Furthermore, the PL maximum of NCs red-shifts as compared with NRs and NWs, which is due to the slightly larger NC size upon hole confinement in the valence band CsPbBr 3 nanocrystal .…”

Section: Resultsmentioning

confidence: 95%

“…The stock shift of NRs and NWs is rather low, which is mainly due to the 2D confined excitons in such systems. 27 Furthermore, the PL maximum of NCs red-shifts as compared with NRs and NWs, which is due to the slightly larger NC size upon hole confinement in the valence band CsPbBr 3 nanocrystal. 28 The PLQY of as-prepared NCs, NRs, and NWs is determined as 90%, 15%, and 24% respectively.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Blue Circularly Polarized Luminescence from Quantum-Confined CsPbBr₃ Nanocrystals with a Different Degree of Shape Anisotropy

Zhu,

Tang,

et al. 2024

J. Phys. Chem. C

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Circularly polarized luminescence is an attractive characteristic of chiral perovskite nanocrystals, as it opens possibilities for applications such as spin-polarized light-emitting diodes and chiral light-selective photodetectors. While previous research has mainly focused on green- and red-emitting chiral perovskite nanocrystals, the exploration of blue-emitting counterparts with efficient circularly polarized luminescence activity is still in its early stages. Here, we synthesize nanocubes, nanoribbons, and nanowires of CsPbBr3 perovskites, which exhibited strong blue emission thanks to quantum confinement in at least two dimensions. Their chiral induction is achieved by attaching chiral molecules (R/S-methylbenzylammonium bromide) to the surface of nanocrystals, resulting in circular dichroism and circularly polarized luminescence. Upon attachment of chiral ligands, the average absorption dissymmetry factor, |gabs|, reached 9 × 10–5 for nanocubes, 1.5 × 10–4 for nanoribbons, and 2.9 × 10–4 for nanowires, thus clearly revealing shape-dependence. Moreover, we achieved blue circular polarized luminescence for all three kinds of samples, with the average luminescence dissymmetry factor, |glum|, of 1.4 × 10–4, 4 × 10–4, and 5.2 × 10–4 for nanocubes, nanoribbons, and nanowires, respectively.

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Section: Resultsmentioning

confidence: 95%

Section: ■ Results and Discussionmentioning

confidence: 99%

Blue Circularly Polarized Luminescence from Quantum-Confined CsPbBr₃ Nanocrystals with a Different Degree of Shape Anisotropy

Zhu,

Tang,

et al. 2024

J. Phys. Chem. C

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“…The results of inverse exciton Stokes shift dependence between the pure and Mn-alloy NPls as a function of the thickness (size) are nicely summarized in Figure e. Earlier inverse size-dependent Stokes shift was observed in CsPbBr 3 NPls compared to corresponding nanocubes, where a clear understanding remains blurred . It should be mentioned that in the literature sometimes researchers talk about the increase in Stokes shift upon Mn doping, which is basically the shift between exciton absorption and Mn PL emission .…”

mentioning

confidence: 75%

“…Earlier inverse size-dependent Stokes shift was observed in CsPbBr 3 NPls compared to corresponding nanocubes, where a clear understanding remains blurred. 44 It should be mentioned that in the literature sometimes researchers talk about the increase in Stokes shift upon Mn doping, which is basically the shift between exciton absorption and Mn PL emission. 27 However, this is not true exciton Stokes shift (but apparent Stokes shift) as the absorption states and emission states involve different species, and this is different from the present study.…”

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confidence: 99%

Giant Exciton Stokes Shift in Interfacially Prepared Cs(Mn/Pb)Cl₃ Alloy Nanoplatelets

Das

Debnath

2023

J. Phys. Chem. Lett.

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Controlling the reabsorption of light by an emitting material is one of the keys to improving the performance of light-emitting devices. We prepare a set of size-dependent Cs(Mn/Pb)Cl 3 alloy nanoplatelets (NPls) with substantial enhancement in the exciton Stokes shift, reducing the light-reabsorption significantly. We perform interfacial Mn-alloying using a shuttling ligand that transports MnCl 2 from aqueous to nonaqueous phase and delivers it to NPls. While the exciton Stokes shift in 2−5 monolayer (ML) CsPbBr 3 NPls rises from 20 to 108 meV, the exciton Stokes shift increases drastically up to 600 meV in 2 ML Cs(Mn/Pb)Cl 3 NPls and further reduces upon increasing the thickness. Moreover, the exciton PL peak in the Mn-alloy NPls remains unperturbed by the quantum-confinement effect. A model based on the interplay between Mn 2+ /Mn 3+ during the charge transfer process is proposed, accounting for such a large exciton Stokes shift. Finally, we utilize the large exciton Stokes-shifted alloy NPls for successful demonstration of white-light generation.

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“…The Huang–Rhys factor reflects the strength of exciton–phonon interaction . Two-dimensional (2D) LHPs also exhibit broad emission characteristics assigned to the STE mechanism because of strong exciton–phonon coupling, as well as Stokes shifts of the free excitons due to quantum confinement effects. − However, this explanation for broad emission is currently strongly debated, citing the existence of halide vacancy trap states. Using a combined experimental–computational study, Kahmann et al demonstrated that the broad emission in 2D LHP originates both from halide vacancies' trapped states and STE.…”

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confidence: 99%

How Does Local Strain Affect Stokes Shifts in Halide Double Perovskite Nanocrystals?

Shaek,

Khalfin,

Massasa

et al. 2023

Chem. Mater.

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Lead-free perovskite nanocrystals are of interest due to their nontoxicity and potential application in the display industry. However, engineering their optical properties is nontrivial and demands an understanding of emission from both self-trapped and free excitons. Here, we focus on tuning silver-based double perovskite nanocrystals' optical properties via two iso-valent dopants, Bi and Sb. The photoluminescence quantum yield of the intrinsic Cs 2 Ag 1−y Na y InCl 6 perovskite increased dramatically upon doping. However, the two dopants affect the optical properties very differently. We hypothesize that the differences arise from their differences in electronic level contributions and ionic sizes. This hypothesis is validated through absorption and temperature dependence photoluminescence measurements, namely, by employing the Huang−Rhys factor, which indicates the coupling of the exciton to the lattice environment. The larger ionic size of Bi also plays a role in inducing significant microstraining verified via synchrotron measurements. These differences make Bi more sensitive to doping concentration over antimony which displays brighter emission (QY ∼40%). Such understanding is important for engineering optical properties in double perovskites, especially in light of recent achievements in boosting the photoluminescence quantum yield.

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Inverse size-dependent Stokes shift in strongly quantum confined CsPbBr₃ perovskite nanoplates

Abstract: We observe that different growth conditions and resulting morphologies of CsPbBr3 nanocrystals yield opposite stokes shift size-dependent trends. This emphasizes the different photo-physics for quantum-confined nanoplate and nanocube morphologies.

Cited by 7 publications

References 57 publications

Blue Circularly Polarized Luminescence from Quantum-Confined CsPbBr₃ Nanocrystals with a Different Degree of Shape Anisotropy

Blue Circularly Polarized Luminescence from Quantum-Confined CsPbBr₃ Nanocrystals with a Different Degree of Shape Anisotropy

Giant Exciton Stokes Shift in Interfacially Prepared Cs(Mn/Pb)Cl₃ Alloy Nanoplatelets

How Does Local Strain Affect Stokes Shifts in Halide Double Perovskite Nanocrystals?

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Inverse size-dependent Stokes shift in strongly quantum confined CsPbBr3 perovskite nanoplates

Abstract: We observe that different growth conditions and resulting morphologies of CsPbBr3 nanocrystals yield opposite stokes shift size-dependent trends. This emphasizes the different photo-physics for quantum-confined nanoplate and nanocube morphologies.

Cited by 7 publications

References 57 publications

Blue Circularly Polarized Luminescence from Quantum-Confined CsPbBr3 Nanocrystals with a Different Degree of Shape Anisotropy

Blue Circularly Polarized Luminescence from Quantum-Confined CsPbBr3 Nanocrystals with a Different Degree of Shape Anisotropy

Giant Exciton Stokes Shift in Interfacially Prepared Cs(Mn/Pb)Cl3 Alloy Nanoplatelets

How Does Local Strain Affect Stokes Shifts in Halide Double Perovskite Nanocrystals?

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Inverse size-dependent Stokes shift in strongly quantum confined CsPbBr₃ perovskite nanoplates

Blue Circularly Polarized Luminescence from Quantum-Confined CsPbBr₃ Nanocrystals with a Different Degree of Shape Anisotropy

Blue Circularly Polarized Luminescence from Quantum-Confined CsPbBr₃ Nanocrystals with a Different Degree of Shape Anisotropy

Giant Exciton Stokes Shift in Interfacially Prepared Cs(Mn/Pb)Cl₃ Alloy Nanoplatelets