Optimized Cation Exchange for Mercury Chalcogenide 2D Nanoplatelets and Its Application for Alloys

Planelles, Josep; Po, Hong; Izquierdo, Eva; Makke, Lina; Gréboval, Charlie; Moghaddam, Nicolas; Khalili, Adrien; Dang, Tung Huu; Chu, Audrey; Pierini, Stefano; Abadie, Claire; Cavallo, Mariarosa; Bossavit, Erwan; Xu, Xiang; Hollander, Philippe; Lhuillier, Emmanuel; Climente, Juan I.; Ithurria, Sandrine

doi:10.1021/acs.chemmater.1c02951

Cited by 20 publications

(60 citation statements)

References 52 publications

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“…The first is alloying, as described in Section 2.3.2 above. Dabard et al demonstrated, for alloyed HgSe 1−x Te x NPL, 62 a bowing effect (i.e., a nonlinear dependence of the bandgap with alloy content) similar to the one observed for CdSe 1−x Te x NPLs 56 (Figure 7d). The introduction of heterostructures (Section 2.7) is another method to achieve spectral tunability while simultaneously enhancing particle stability and PL efficiency.…”

Section: Cation Exchange Onsupporting

confidence: 56%

“…This paradox has been resolved by Dabard et al, who demonstrated that selection rules and band mixing induce similar optically active transitions in the mercury chalcogenide NPLs. 62 The second-factor complicating feature in the optical absorption of colloidal NPLs, excitons, is a distinguishing characteristic of colloidal NPL structures. Excitons, representing a deviation from plane-wave delocalization of electrons and holes, are electron−hole pairs bound by Coulombic attraction at an energy lower than the bandgap of free carriers.…”

Section: Electronic Structure Of a Quantum Well Semiconductormentioning

confidence: 99%

Section: Synthesis and Structure Of Nplsmentioning

confidence: 99%

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

Diroll

Güzeltürk

et al. 2023

Chem. Rev.

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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.

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Section: Cation Exchange Onsupporting

confidence: 56%

Section: Electronic Structure Of a Quantum Well Semiconductormentioning

confidence: 99%

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

Diroll

Güzeltürk

et al. 2023

Chem. Rev.

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“…43 Continuous variation in HgSexTe1-x nanoparticles doping from n to p type by varying the nanoparticle composition has been evidenced by energy band diagram determination and TR-PES measurement. 44 Development of CQDs based solar cells strongly depends on charge collection efficiency. Determining the CQDs/electrode electronic coupling is of high interest.…”

Section: Colloidal Quantum Dotsmentioning

confidence: 99%

High resolution and time resolved photoemission spectroscopy for developing more efficient materials to reduce energy consumption and increase renewable energy production

Silly

2022

EPJ Web Conf.

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Due to the increase of energy consumption and the resulting ecological challenge, a collective awareness leads to the development of renewable energies and more efficient materials to increase the green energy production. Development of efficient photovoltaic materials is very closely related to their chemical and electronic properties. A better knowledge of these imbricated properties is needed, in addition to a better comprehension of their interplay with charge transport mechanisms. Exciton creation and recombination processes, charge transfer and charge collection processes take place at the surface and interface of the photoactive materials. Photoemission spectroscopy as chemical specific and surface sensitive spectroscopic technique is a method of choice on the study of physical phenomena at the origin of photoconversion efficiency. Time resolved photoemission spectroscopy has been recently renewed interest covering time scale from fs to more than seconds. It permits to probe the dynamics of relaxation of photoexcited charges and determine their lifetime. It finds application in various materials used in solar photovoltaics. In this paper, we define the physical and chemical properties determined by the combination of high resolution and time resolved photoemission spectroscopy. We show examples dealing with the development of renewable energy and energy consumption reduction in agreement with the current ecological trend for a better future.

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“…To date, two - dimensional CdTe nanostructures have been reported in the form of zincblende structured NPLs, wurtzite structured nanoribbons and CdTe nanosheets. , In 2013, Pedetti et al optimized the synthesis protocol for the colloidal synthesis of CdTe NPLs with zincblende structure, yielding NPL populations of different thicknesses defined with atomic precision. Despite such advances, the emission PLQY of CdTe NPLs is still limited to ∼1% ,− and no study has so far investigated their emission properties under ionizing radiation excitation.…”

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confidence: 99%

Optical and Scintillation Properties of Record-Efficiency CdTe Nanoplatelets toward Radiation Detection Applications

et al. 2022

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Colloidal CdTe nanoplatelets featuring a large absorption coefficient and ultrafast tunable luminescence coupled with heavy-metal-based composition present themselves as highly desirable candidates for radiation detection technologies. Historically, however, these nanoplatelets have suffered from poor emission efficiency, hindering progress in exploring their technological potential. Here, we report the synthesis of CdTe nanoplatelets possessing a record emission efficiency of 9%. This enables us to investigate their fundamental photophysics using ultrafast transient absorption, temperature-controlled photoluminescence, and radioluminescence measurements, elucidating the origins of exciton-and defectrelated phenomena under both optical and ionizing excitation. For the first time in CdTe nanoplatelets, we report the cumulative effects of a giant oscillator strength transition and exciton fine structure. Simultaneously, thermally stimulated luminescence measurements reveal the presence of both shallow and deep trap states and allow us to disclose the trapping and detrapping dynamics and their influence on the scintillation properties.

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Optimized Cation Exchange for Mercury Chalcogenide 2D Nanoplatelets and Its Application for Alloys

Cited by 20 publications

References 52 publications

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

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

High resolution and time resolved photoemission spectroscopy for developing more efficient materials to reduce energy consumption and increase renewable energy production

Optical and Scintillation Properties of Record-Efficiency CdTe Nanoplatelets toward Radiation Detection Applications

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