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Title: Atomistic Analysis of Room Temperature Quantum Coherence in Two-Dimensional CdSe Nanostructures

Authors:
; ; ; ORCiD logo
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1356270
Grant/Contract Number:
SC00014607
Resource Type:
Journal Article: Published Article
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 17; Journal Issue: 4; Related Information: CHORUS Timestamp: 2017-10-30 06:51:59; Journal ID: ISSN 1530-6984
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English

Citation Formats

Pal, Sougata, Nijjar, Parmeet, Frauenheim, Thomas, and Prezhdo, Oleg V. Atomistic Analysis of Room Temperature Quantum Coherence in Two-Dimensional CdSe Nanostructures. United States: N. p., 2017. Web. doi:10.1021/acs.nanolett.6b05368.
Pal, Sougata, Nijjar, Parmeet, Frauenheim, Thomas, & Prezhdo, Oleg V. Atomistic Analysis of Room Temperature Quantum Coherence in Two-Dimensional CdSe Nanostructures. United States. doi:10.1021/acs.nanolett.6b05368.
Pal, Sougata, Nijjar, Parmeet, Frauenheim, Thomas, and Prezhdo, Oleg V. Thu . "Atomistic Analysis of Room Temperature Quantum Coherence in Two-Dimensional CdSe Nanostructures". United States. doi:10.1021/acs.nanolett.6b05368.
@article{osti_1356270,
title = {Atomistic Analysis of Room Temperature Quantum Coherence in Two-Dimensional CdSe Nanostructures},
author = {Pal, Sougata and Nijjar, Parmeet and Frauenheim, Thomas and Prezhdo, Oleg V.},
abstractNote = {},
doi = {10.1021/acs.nanolett.6b05368},
journal = {Nano Letters},
number = 4,
volume = 17,
place = {United States},
year = {Thu Mar 02 00:00:00 EST 2017},
month = {Thu Mar 02 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1021/acs.nanolett.6b05368

Citation Metrics:
Cited by: 5works
Citation information provided by
Web of Science

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  • We report on the results of studying quasi-two-dimensional nanostructures synthesized here in the form of semiconducting CdSe nanoplatelets with a characteristic longitudinal size of 20–70 nm and a thick-ness of a few atomic layers. Their morphology is studied using TEM and AFM and X-ray diffraction analysis; the crystal structure and sizes are determined. At room and cryogenic temperatures, the spectra and kinetics of the photoluminescence of such structures (quantum wells) are investigated. A hybrid light-emitting diode operating on the basis of CdSe nanoplatelets as a plane active element (emitter) is developed using the organic materials TAZ and TPD to formmore » electron and hole transport layers, respectively. The spectral and current-voltage characteristics of the constructed device with a radiation wavelength λ = 515 nm are obtained. The device triggering voltage is 5.5 V (visible glow). The use of quasi-two-dimensional structures of this type is promising for hybrid light-emitting diodes with pure color and low operating voltages.« less
  • No abstract prepared.
  • We perform photoluminescence excitation measurements on individual CdSe/ZnS nanocrystal quantum dots (NCQDs) at room temperature to study optical transition energies and broadening. The observed features in the spectra are identified and compared to calculated transition energies using an effective mass model. The observed broadening is attributed to phonon broadening, spectral diffusion, and size and shape inhomogeneity. The former two contribute to the broadening transitions in individual QDs, while the latter contributes to the QD-to-QD variation. We find that phonon broadening is often not the dominant contribution to transition line widths, even at room temperature, and that broadening does not necessarilymore » increase with transition energy. This may be explained by differing magnitude of spectral diffusion for different quantum-confined states.« less
  • We observed a photo-switching effect in [Cu{sup II}(1,4,8,11-tetraazacyclodecane)]{sub 2}[Mo{sup IV}(CN){sub 8}]{center_dot}10H{sub 2}O by irradiation with 410-nm light around room temperature using infrared spectroscopy. This photo-switching is caused by the photo-induced charge transfer from Mo{sup IV} to Cu{sup II}. The photo-induced phase thermally relaxed to the initial phase with a half-life time of 2.7 Multiplication-Sign 10{sup 1}, 6.9 Multiplication-Sign 10{sup 1}, and 1.7 Multiplication-Sign 10{sup 2} s at 293, 283, and 273 K, respectively. The relaxation process was analyzed using Hauser's equation, k=k{sub 0}exp[-(E{sub a}+E{sub a}{sup *}{gamma}) /k{sub B}T], where k is the rate constant of relaxation, k{sub 0} is themore » frequency factor, E{sub a} is the activation energy, E{sub a}{sup *} is the additional activation energy due to the cooperativity, and {gamma} is the fraction of the photo-induced phase. k{sub 0}, E{sub a}, and E{sub a}{sup *} were evaluated as 1.28 Multiplication-Sign 10{sup 7}{+-} 2.6 s{sup -1}, 4002 {+-} 188 cm{sup -1}, and 546 {+-} 318 cm{sup -1}, respectively. The value of E{sub a} is much larger than that of the relaxation process for the typical light-induced spin crossover effect (E{sub a} Almost-Equal-To 1000 cm{sup -1}). Room-temperature photo-switching is an important issue in the field of optical functional materials. The present system is useful for the demonstration of high-temperature photo-switching material.« less