Explaining observed stability of excitons in highly excited CdSe nanoplatelets

Flórez, F. García; Kulkarni, Aditya; Siebbeles, Laurens D. A.; Stoof, H. T. C.

doi:10.1103/physrevb.100.245302

Cited by 14 publications

(57 citation statements)

References 104 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This result is highlighted because it represents the experimental findings of Refs. [15,29]. Therefore, the ratio of permittivities / sol 6.99 is physically meaningful in that it compares favorably with other independent measurements on CdSe.…”

Section: Excitonssupporting

confidence: 73%

“…For the purpose of relating our results to an experimentally realizable case, we exemplify the use of our theory by setting the parameters of the model corresponding to CdSe nanoplatelets in hexane solvent at room temperature [15,29]. As a consequence, we use for the electron and hole masses the values m e = 0.27 m 0 and m h = 0.45 m 0 , where m 0 is the fundamental electron mass, corresponding to a thickness of 4.5 CdSe monolayers having d = 1.37 nm, given as n = 4 in Ref.…”

Section: Excitonsmentioning

confidence: 99%

“…10 shows not only the groundstate energy but also the energy of the first several excited s-wave states at the fixed ratio d * /a 0 4.37 corresponding to the experiment studied in Refs. [15,29]. Furthermore, each energy is obtained from the quantum-confined Rytova-Keldysh potential, the Struve-Neumann potential, and the Rytova-Keldysh potential.…”

Section: Excitonsmentioning

confidence: 99%

See 2 more Smart Citations

Effects of material thickness and surrounding dielectric medium on Coulomb interactions and two-dimensional excitons

2020

Self Cite

View full text Add to dashboard Cite

We examine the impact of quantum confinement on the interaction potential between two charges in twodimensional semiconductor nanosheets in solution. The resulting effective potential depends on two length scales, namely, the thickness d and an emergent length scale d * ≡ d/ sol , where is the permittivity of the nanosheet and sol is the permittivity of the solvent. In particular, quantum confinement, and not electrostatics, is responsible for the logarithmic behavior of the effective potential for separations smaller than d, instead of the one-over-distance bulk Coulomb interaction. Finally, we corroborate that the exciton binding energy also depends on the two-dimensional Bohr radius a 0 in addition to the length scales d and d * and analyze the consequences of this dependence.

show abstract

Section: Excitonssupporting

confidence: 73%

Section: Excitonsmentioning

confidence: 99%

Section: Excitonsmentioning

confidence: 99%

See 1 more Smart Citation

Effects of material thickness and surrounding dielectric medium on Coulomb interactions and two-dimensional excitons

2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…The most important differences are discussed in Ref. [52]. Armed with this newfound understanding, it follows that the formation of more complex species is very likely as well.…”

Section: Introductionmentioning

confidence: 99%

“…Even though excitons and biexcitons have been thoroughly experimented with, especially in three-dimensional semiconductors, it was not until recently that an unexpected stability of excitons in two-dimensional CdSe nanoplatelets at high densities was observed, which was, in turn, explained by the rather unimportant screening effects of the free charges in this case [51,52]. Note that these recent experiments [51] clearly show that the physics of excitons in two-dimensional semiconductors is significantly different from that in three dimensions, as, for example, described in Ref.…”

Section: Introductionmentioning

confidence: 99%

Biexcitons in highly excited CdSe nanoplatelets

2020

Self Cite

View full text Add to dashboard Cite

We present the phase diagram of free charges (electrons and holes), excitons, and biexcitons in highly excited CdSe nanoplatelets that predicts a crossover to a biexciton-dominated region at easily attainable low temperatures or high photoexcitation densities. Our findings extend previous work describing only free charges and excitons by introducing biexcitons into the equation of state, while keeping the exciton and biexciton binding energies constant in view of the relatively low density of free charges in this material. Our predictions are experimentally testable in the near future and offer the prospect of creating a quantum degenerate, and possibly even superfluid, biexciton gas. Furthermore, we also provide simple expressions giving analytical insight into the regimes of photoexcitation densities and temperatures in which excitons and biexcitons dominate the response of the nanoplatelets.

show abstract

2D II–VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration

Diroll

Güzeltürk

et al. 2023

Chem. Rev.

View full text Add to dashboard Cite

The field of colloidal synthesis of semiconductors emerged 40 years ago and has reached a certain level of maturity thanks to the use of nanocrystals as phosphors in commercial displays. In particular, II−VI semiconductors based on cadmium, zinc, or mercury chalcogenides can now be synthesized with tailored shapes, composition by alloying, and even as nanocrystal heterostructures. Fifteen years ago, II−VI semiconductor nanoplatelets injected new ideas into this field. Indeed, despite the emergence of other promising semiconductors such as halide perovskites or 2D transition metal dichalcogenides, colloidal II−VI semiconductor nanoplatelets remain among the narrowest room-temperature emitters that can be synthesized over a wide spectral range, and they exhibit good material stability over time. Such nanoplatelets are scientifically and technologically interesting because they exhibit optical features and production advantages at the intersection of those expected from colloidal quantum dots and epitaxial quantum wells. In organic solvents, gram-scale syntheses can produce nanoparticles with the same thicknesses and optical properties without inhomogeneous broadening. In such nanoplatelets, quantum confinement is limited to one dimension, defined at the atomic scale, which allows them to be treated as quantum wells. In this review, we discuss the synthetic developments, spectroscopic properties, and applications of such nanoplatelets. Covering growth mechanisms, we explain how a thorough understanding of nanoplatelet growth has enabled the development of nanoplatelets and heterostructured nanoplatelets with multiple emission colors, spatially localized excitations, narrow emission, and high quantum yields over a wide spectral range. Moreover, nanoplatelets, with their large lateral extension and their thin short axis and low dielectric surroundings, can support one or several electron−hole pairs with large exciton binding energies. Thus, we also discuss how the relaxation processes and lifetime of the carriers and excitons are modified in nanoplatelets compared to both spherical quantum dots and epitaxial quantum wells. Finally, we explore how nanoplatelets, with their strong and narrow emission, can be considered as ideal candidates for pure-color light emitting diodes (LEDs), strong gain media for lasers, or for use in luminescent light concentrators.

show abstract

Explaining observed stability of excitons in highly excited CdSe nanoplatelets

Cited by 14 publications

References 104 publications

Effects of material thickness and surrounding dielectric medium on Coulomb interactions and two-dimensional excitons

Effects of material thickness and surrounding dielectric medium on Coulomb interactions and two-dimensional excitons

Biexcitons in highly excited CdSe nanoplatelets

2D II–VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration

Contact Info

Product

Resources

About