Lateral quantum confinement regulates charge carrier transfer and biexciton interaction in CdSe/CdSeS core/crown nanoplatelets

Yao, Yige; Bao, Xiaotian; Zhu, Yunke; Sui, Xinyu; Ai, Hu; Bai, Peng; Wang, Shufeng; Yang, Hong; Liu, Xinfeng; Gao, Yunan

doi:10.1007/s12274-023-5542-0

Cited by 4 publications

(8 citation statements)

References 69 publications

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“…The experimental data are well fitted by the exponential function, as stated by eq , confirming this temperature-dependent transfer. As the transfer rate follows well with the description of the Marcus model, both in the aspect of driving force and temperature, we are confident that the charge carrier transfer mechanism is predominant. Note that although the intensity increase is not recognizable below 90 K, it is reasonable to assume in the following discussion that the transfer rate still follows eq in our measurement range.…”

Section: Resultssupporting

confidence: 68%

“…At high temperatures like 300 K (red line), the PL intensity rises first after the instrument response, contrasted with the immediate decay of the low-temperature traces (purple line). As the core and the crown form a type-I band alignment, this intensity rise is attributed to the charge carrier transfer from the crown to the core, which has been observed at room temperature in our previous work . The lifetimes (namely, the reciprocal of the transfer rate k CT ) of the rise-channel of the TRPL traces are fitted by a multiexponential function (Supporting Information Section 4).…”

Section: Resultsmentioning

confidence: 90%

“…As the core and the crown form a type-I band alignment, this intensity rise is attributed to the charge carrier transfer from the crown to the core, which has been observed at room temperature in our previous work. 37 The lifetimes (namely, the reciprocal of the transfer rate k CT ) of the rise-channel of the TRPL traces are fitted by a multi- According to the Marcus model of the charge carrier transfer, 53,54 the transfer rate is stated as…”

Section: ■ Introductionmentioning

confidence: 99%

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Temperature-Regulated In-Plane Exciton Dynamics in CdSe/CdSeS Colloidal Quantum Well Heterostructures

Yao,

Zhu,

et al. 2023

ACS Photonics

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Colloidal semiconductor quantum wells (CQWs) have attracted wide attention in both fundamental research and photonics applications for their excellent optical properties. In this work, we reveal rich in-plane exciton dynamics of the CdSe/CdSeS CQW heterostructure through picosecond time-resolved photoluminescence spectroscopy in a wide temperature range (300−5 K). The in-plane charge carrier transfer dominates the exciton dynamics at high temperatures above about 60 K. With a decrease in temperature, the inner processes of the exciton fine-structure start to compete with the transfer process and finally dominate the dynamics. We quantitatively analyze the competition between these processes by a transfer-coupled three-state model. Moreover, we resolve the center-of-mass motion of excitons experimentally, whose energy is modulated by the core/crown heterostructure. Our work provides new insight into the exciton dynamics in CQWs and demonstrates them as an excellent platform to study exciton physics, with results that are generally applicable to various in-plane 2D semiconductor heterostructures.

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Section: Resultssupporting

confidence: 68%

Section: Resultsmentioning

confidence: 90%

Section: ■ Introductionmentioning

confidence: 99%

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Temperature-Regulated In-Plane Exciton Dynamics in CdSe/CdSeS Colloidal Quantum Well Heterostructures

Yao,

Zhu,

et al. 2023

ACS Photonics

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“…Recently, we found that carrier transfer from the crown to the core takes tens of picoseconds. 46 Under femtosecond excitation, the photogenerated carriers in the crown would contribute little to the ASE process of the CdSe core. Instead, the volume ratio of the CdSe core, i.e., the actual gain materials, in the whole film is decreased, resulting in a relatively higher ASE threshold.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…However, the charge carrier transfer rate has to be considered from different pump conditions. Recently, we found that carrier transfer from the crown to the core takes tens of picoseconds . Under femtosecond excitation, the photogenerated carriers in the crown would contribute little to the ASE process of the CdSe core.…”

Section: Resultsmentioning

confidence: 99%

Low-Threshold Single-Mode Microlasers from Green CdSe/CdSeS Core/Alloyed-Crown Nanoplatelets

Zhu

Niu

et al. 2023

ACS Photonics

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Colloidal nanoplatelets (NPLs), a class of semiconductor nanocrystals, have attracted considerable attention as a promising gain material for their ultralow amplified spontaneous emission (ASE) and lasing thresholds. However, there exist spectral gaps, especially in the green-color range, that NPLs cannot fully cover. The recently developed CdSe/CdSeS core/ alloyed-crown NPLs with excellent tunability across the greencolor range offer the possibility to remedy this deficiency. Here, the ASE and lasing characteristics of this new type of NPL are investigated. A remarkably low ASE threshold of 16 μJ/cm 2 at 522 nm is measured, the lowest among core/crown NPLs. Microlasers are fabricated by spin-coating them on second-order distributed feedback (DFB) cavities developed in silicon nitride (SiN) substrates. The microlasers exhibit an ultralow lasing threshold of 9 μJ/cm 2 at 522 nm. Moreover, they can cover a spectral range of 505−535 nm with all clean single-mode emissions. Picosecond time-and spectral-resolved photoluminescence (PL) spectroscopy reveals that the gain band is determined by the biexciton emission bandwidth. The vigorous development of NPLs with low lasing thresholds in a broad spectral range will greatly facilitate the realization of nanocrystal-based lasers.

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Colloidal II–VI nanoplatelets for optoelectronic devices: Progress and perspectives

Hu,

Ma,

Yang

et al. 2024

Nano Res.

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Lateral quantum confinement regulates charge carrier transfer and biexciton interaction in CdSe/CdSeS core/crown nanoplatelets

Cited by 4 publications

References 69 publications

Temperature-Regulated In-Plane Exciton Dynamics in CdSe/CdSeS Colloidal Quantum Well Heterostructures

Temperature-Regulated In-Plane Exciton Dynamics in CdSe/CdSeS Colloidal Quantum Well Heterostructures

Low-Threshold Single-Mode Microlasers from Green CdSe/CdSeS Core/Alloyed-Crown Nanoplatelets

Colloidal II–VI nanoplatelets for optoelectronic devices: Progress and perspectives

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