Random Lasing with Systematic Threshold Behavior in Films of CdSe/CdS Core/Thick-Shell Colloidal Quantum Dots

Gollner, Claudia; Ziegler, Johannes; Proteşescu, Loredana; Dirin, Dmitry N.; Lechner, R. T.; Fritz‐Popovski, Gerhard; Sytnyk, Mykhailo; Yakunin, Sergii; Rotter, Stefan; Amin, Amir Abbas Yousefi; Vidal, Cynthia; Hrelescu, Calin; Klar, Thomas A.; Kovalenko, Maksym V.; Heiß, Wolfgang

doi:10.1021/acsnano.5b02739

Cited by 52 publications

(62 citation statements)

References 72 publications

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“…In the last few years, perovskites and traditional colloidal semiconductor quantum dots (QDs) especially the Cd 2+ ‐based QDs such as CdSe and CdTe emerged as good candidates for the development of random lasers since their unique and attractive optical characteristics, such as high quantum yield (QY), small Stokes shifts, and narrow emission bandwidths, can facilitate the ultrafast build‐up of population inversion and the subsequent optical amplification at a low pump energy density . Considerable efforts have been invested and remarkable progress has been made on the design and fabrication of highly efficient random lasers with high spectral purities based on the perovskites and Cd 2+ ‐based QDs in simple device configurations . However, the intrinsic instability as well as the severe toxicity are still significant impediments to deploying perovskites and Cd 2+ ‐based QDs as next‐generation light‐emitting materials for future ultrastable and low‐threshold random lasing applications …”

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confidence: 99%

“…Considerable efforts have been invested and remarkable progress has been made on the design and fabrication of highly efficient random lasers with high spectral purities based on the perovskites and Cd 2+ ‐based QDs in simple device configurations . However, the intrinsic instability as well as the severe toxicity are still significant impediments to deploying perovskites and Cd 2+ ‐based QDs as next‐generation light‐emitting materials for future ultrastable and low‐threshold random lasing applications …”

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confidence: 99%

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Ultrastable and Low‐Threshold Random Lasing from Narrow‐Bandwidth‐Emission Triangular Carbon Quantum Dots

Yuan

Shi

et al. 2018

Advanced Optical Materials

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colloidal semiconductor quantum dots (QDs) especially the Cd 2+ -based QDs such as CdSe and CdTe emerged as good candidates for the development of random lasers since their unique and attractive optical characteristics, such as high quantum yield (QY), small Stokes shifts, and narrow emission bandwidths, can facilitate the ultrafast build-up of population inversion and the subsequent optical amplification at a low pump energy density. [4][5][6] Considerable efforts have been invested and remarkable progress has been made on the design and fabrication of highly efficient random lasers with high spectral purities based on the perovskites and Cd 2+ -based QDs in simple device configurations. [7][8][9][10] However, the intrinsic instability as well as the severe toxicity are still significant impediments to deploying perovskites and Cd 2+ -based QDs as next-generation light-emitting materials for future ultrastable and low-threshold random lasing applications. [7][8][9][10] The bandgap emission carbon quantum dots (BE-CQDs) have recently emerged as a promising alternative to perovskites and traditional semiconductor QDs for optoelectronic devices, such as solution-processed electroluminescent light-emitting diodes (LEDs) [11][12][13] and lasers, by taking advantage of carbon's intrinsic merits of high stability, low cost, high abundance, and environment friendliness. [14][15][16][17][18][19][20][21] In our recent work, for the first time, we have realized full-color random lasing with lasing thresholds in the range of 2.1-5.8 mJ cm −2 in blue, green, red, and white colors based on bright multicolor fluorescent BE-CQDs. [14] The random lasers show much better operating stability than those of perovskites and Cd 2+ -based QDs, laying a solid foundation for developing the next-generation laser technology. [7][8][9][10][22][23][24] However, the large Stokes shifts (>80 nm) and the large full width at half maximum (FWHM > 80 nm) of the BE-CQDs inevitably result in the dissipation of exciton energy into heat and prevent sustaining population inversion during the pumping process, thus fundamentally limiting the further performance improvement especially on pump thresholds for the random lasing. [14][15][16][17][18][19][20][21] Without a doubt, the best approach to realizing tunable stable CQDs-based random lasers with a much lower pump threshold for lasing is to develop bright multicolor fluorescent CQDs with small Stokes shifts (<20 nm) and small FWHM (<40 nm).Most recently, we have demonstrated the first synthesis of highly efficient narrow bandwidth emission triangular CQDsThe development of ultrastable and low-threshold random lasers has long been the subject of intense academic research, in anticipation for widespread applications spanning from military weapon devices, biomedical therapy, and materials processing to energy savings. Reported here is the first example of ultrastable and low-threshold random lasing emissions ranging from blue to red based on narrow bandwidth emission triangular carbon quantum dots (CQDs)....

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confidence: 99%

Ultrastable and Low‐Threshold Random Lasing from Narrow‐Bandwidth‐Emission Triangular Carbon Quantum Dots

Yuan

Shi

et al. 2018

Advanced Optical Materials

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“…Figure a shows the emission spectra of a drop‐cast NPL‐i‐TDs film under femtosecond pulsed excitation (λ = 400 nm) and increasing pump fluence. We observe an ASE band at the high‐energy side of the PL peak, which indicates repulsive exciton interactions . The ASE threshold is 270 µJ cm −2 , which is significantly higher than what is obtained on CdSe core‐only and on CdSe/CdS NPLs with a thin shell,5c but within one order of magnitude comparable to other CdSe/CdS core/shell structures 18a,23b,33a,34.…”

Section: Resultsmentioning

confidence: 99%

“…We observe an ASE band at the high‐energy side of the PL peak, which indicates repulsive exciton interactions . The ASE threshold is 270 µJ cm −2 , which is significantly higher than what is obtained on CdSe core‐only and on CdSe/CdS NPLs with a thin shell,5c but within one order of magnitude comparable to other CdSe/CdS core/shell structures 18a,23b,33a,34. While the complex shell morphology of the NPLs‐i‐TDs is not optimal for ASE and lasing, these structures provide a peculiar exciton delocalization, and therefore, they can be very appealing for applications where electron and holes should be localized in different portions of the nanocrystal volume.…”

Section: Resultsmentioning

confidence: 99%

Core/Shell CdSe/CdS Bone‐Shaped Nanocrystals with a Thick and Anisotropic Shell as Optical Emitters

Castelli

Dhanabalan

Polovitsyn

et al. 2019

Advanced Optical Materials

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Colloidal core/shell nanocrystals are key materials for optoelectronics, enabling control over essential properties via precise engineering of the shape, thickness, and crystal structure of their shell. Here, the growth protocol for CdS branched nanocrystals is applied on CdSe nanoplatelet seeds and bone‐shaped heterostructures are obtained with a highly anisotropic shell. Surprisingly, the nanoplatelets withstand the high growth temperature of 350 °C and structures with a CdSe nanoplatelet core that is overcoated by a shell of cubic CdS are obtained, on top of which tetrahedral CdS structures with hexagonal lattice are formed. These complex core/shell nanocrystals show a band‐edge emission around 657 nm with a photoluminescence quantum yield of ≈42% in solution, which is also retained in thin films. Interestingly, the nanocrystals manifest simultaneous red and green emission and the relatively long wavelength of the green emission indicates charge recombination at the cubic/hexagonal interface of the CdS shell. The nanocrystal films show amplified spontaneous emission, random lasing, and distributed feedback lasing when the material is deposited on suitable gratings. This work stimulates the design and fabrication of more exotic core/shell heterostructures where charge carrier delocalization, dipole moment, and other optical and electrical properties can be engineered.

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“…1D rod-shaped nanocrystals (rods, wires, belts) are of particular interest as they have shown a lower threshold for lasing in addition to exhibiting directional and polarized emission12. The knowledge gained from quantum dot solids indicates that close packing is necessary to allow sufficient volume fraction of nanocrystals to overcome losses due to non-radiative processes and allow ASE345. Therefore harnessing the collective emission from colloidal semiconductor nanorods through organized assembly has enormous potential for next generation lasers with particular interest for their application in integratable nanophotonics as components for all-optical integrated circuits67.…”

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Assembling Ordered Nanorod Superstructures and Their Application as Microcavity Lasers

Liu

Singh

Guo

et al. 2017

Sci Rep

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Herein we report the formation of multi-layered arrays of vertically aligned and close packed semiconductor nanorods in perfect registry at a substrate using electric field assisted assembly. The collective properties of these CdSexS1-x nanorod emitters are harnessed by demonstrating a relatively low amplified spontaneous emission (ASE) threshold and a high net optical gain at medium pump intensity. The importance of order in the system is highlighted where a lower ASE threshold is observed compared to disordered samples.

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Random Lasing with Systematic Threshold Behavior in Films of CdSe/CdS Core/Thick-Shell Colloidal Quantum Dots

Cited by 52 publications

References 72 publications

Ultrastable and Low‐Threshold Random Lasing from Narrow‐Bandwidth‐Emission Triangular Carbon Quantum Dots

Ultrastable and Low‐Threshold Random Lasing from Narrow‐Bandwidth‐Emission Triangular Carbon Quantum Dots

Core/Shell CdSe/CdS Bone‐Shaped Nanocrystals with a Thick and Anisotropic Shell as Optical Emitters

Assembling Ordered Nanorod Superstructures and Their Application as Microcavity Lasers

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