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Lu, X., Zhou, J., Gelloz, B. & Sychugov, I. (2024). Mechanism of quantum yield enhancement in Si quantum dots by high-pressure water vapor annealing from single-dot studies. Applied Physics Letters, 125(7), Article ID 071110.
Open this publication in new window or tab >>Mechanism of quantum yield enhancement in Si quantum dots by high-pressure water vapor annealing from single-dot studies
2024 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 125, no 7, article id 071110Article in journal (Refereed) Published
Abstract [en]

High-pressure water vapor annealing (HWA) was recently demonstrated as a method that can substantially improve the photoluminescence quantum yield (PLQY) of silicon quantum dots (Si QDs) with the oxide shell. In this Letter, the mechanism of this enhancement is studied optically on a single-dot level. HWA treatment is performed on Si QDs formed on a silicon-on-insulator wafer, and their photoluminescence (PL) properties were examined before and after the treatment. Our experiments show a 2.5 time enhancement in the average blinking duty cycle of Si QDs after 2.6 MPa HWA treatment without changing the average ON-state PL intensity. This observation proves the carrier trapping process is suppressed on the HWA-built Si/SiO2 interface. We also discussed the mechanism behind the PLQY enhancement of HWA-treated Si QDs by comparing single-dot-level data to reported ensemble PL Si QDs results. HWA treatment is found to mainly brighten "grey" (not 100% efficient) QDs, a mechanism different from changing dark (non-emitting) to bright (100% efficient) Si QDs by ligand passivation.

Place, publisher, year, edition, pages
AIP Publishing, 2024
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-352537 (URN)10.1063/5.0223989 (DOI)001291955700007 ()2-s2.0-85201591959 (Scopus ID)
Note

QC 20240903

Available from: 2024-09-03 Created: 2024-09-03 Last updated: 2024-09-03Bibliographically approved
Radamson, H. H., Hallén, A., Sychugov, I. & Azarov, A. (2023). Analytical Methods and Instruments for Micro- and Nanomaterials. Switzerland: Springer Nature
Open this publication in new window or tab >>Analytical Methods and Instruments for Micro- and Nanomaterials
2023 (English)Book (Refereed)
Place, publisher, year, edition, pages
Switzerland: Springer Nature, 2023
Keywords
nanotechnology
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-364571 (URN)10.1007/978-3-031-26434-4 (DOI)978-3-031-26433-7 (ISBN)
Note

QC 20250617

Available from: 2025-06-16 Created: 2025-06-16 Last updated: 2025-06-17Bibliographically approved
Ohlin, H., Frisk, T., Sychugov, I. & Vogt, U. (2023). Comparing metal assisted chemical etching of N and P-type silicon nanostructures. Micro and Nano Engineering, 19, Article ID 100178.
Open this publication in new window or tab >>Comparing metal assisted chemical etching of N and P-type silicon nanostructures
2023 (English)In: Micro and Nano Engineering, E-ISSN 2590-0072, Vol. 19, article id 100178Article in journal (Refereed) Published
Abstract [en]

Metal assisted chemical etching is a promising method for fabricating high aspect ratio micro- and nanostructures in silicon. Previous results have suggested that P-type and N-type silicon etches with different degrees of anisotropy, questioning the use of P-type silicon for nanostructures. In this study, we compare processing X-ray zone plate nanostructures in N and P-type silicon through metal assisted chemical etching with a gold catalyst. Fabricated zone plates were cleaved and studied with a focus on resulting verticality, depth and porosity. Results show that for high aspect ratio nanostructures, both N and P-type silicon prove to be viable alternatives exhibiting different etch rates, but similarities regarding porosity and etch direction.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
MACE, Metal assisted chemical etching, N-type, Nanostructures, P-type, X-ray diffractive optics, Zone plate
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-330938 (URN)10.1016/j.mne.2023.100178 (DOI)001043751200001 ()2-s2.0-85151536658 (Scopus ID)
Note

QC 20230704

Available from: 2023-07-04 Created: 2023-07-04 Last updated: 2024-02-02Bibliographically approved
Lu, X., Zhou, J., Jash, M. & Sychugov, I. (2023). Luminescent solar concentrator efficiency versus edge solar cell coverage. Optics Letters, 48(16), 4197-4200
Open this publication in new window or tab >>Luminescent solar concentrator efficiency versus edge solar cell coverage
2023 (English)In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 48, no 16, p. 4197-4200Article in journal (Refereed) Published
Abstract [en]

This Letter introduces an analytical approach to estimate the waveguiding efficiency of large-area luminescent solar concentrators (LSCs), where the edges are covered by a var-ied number of mirrors and solar cells. The model provides physically relevant description in the whole range of optical (absorption, scattering) and geometrical (size) parameters of rectangular LSCs. A 19 x 19 cm2 silicon quantum dot -based LSC has been fabricated to verify the theory. Within an experimental error, the predicted waveguiding efficiency matched well the measured one. A critical LSC size, beyond which a part of the device turns inactive, has been deter-mined as N/& alpha; for N attached solar cells (one or two) and LSC material absorption coefficient & alpha;. This model provides a straightforward waveguiding analysis tool for large-area LSCs with different structural parameters relevant for both high concentration ratio and glazing applications.

Place, publisher, year, edition, pages
Optica Publishing Group, 2023
Keywords
Efficiency, Flowcharting, Luminescence, Solar cells, Solar concentrators, Waveguides
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-338673 (URN)10.1364/OL.496595 (DOI)001065642900003 ()37581991 (PubMedID)2-s2.0-85168069486 (Scopus ID)
Note

QC 20231031

Available from: 2023-10-31 Created: 2023-10-31 Last updated: 2023-10-31Bibliographically approved
Yang, Y., Dev, A., Sychugov, I., Hägglund, C. & Zhang, S. L. (2023). Plasmon-Enhanced Fluorescence of Single Quantum Dots Immobilized in Optically Coupled Aluminum Nanoholes. The Journal of Physical Chemistry Letters, 14(9), 2339-2346
Open this publication in new window or tab >>Plasmon-Enhanced Fluorescence of Single Quantum Dots Immobilized in Optically Coupled Aluminum Nanoholes
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2023 (English)In: The Journal of Physical Chemistry Letters, E-ISSN 1948-7185, Vol. 14, no 9, p. 2339-2346Article in journal (Refereed) Published
Abstract [en]

Fluorescence-based optical sensing techniques have continually been explored for single-molecule detection targeting myriad biomedical applications. Improving signal-to-noise ratio remains a prioritized effort to enable unambiguous detection at single-molecule level. Here, we report a systematic simulation-assisted optimization of plasmon-enhanced fluorescence of single quantum dots based on nanohole arrays in ultrathin aluminum films. The simulation is first calibrated by referring to the measured transmittance in nanohole arrays and subsequently used for guiding their design. With an optimized combination of nanohole diameter and depth, the variation of the square of simulated average volumetric electric field enhancement agrees excellently with that of experimental photoluminescence enhancement over a large range of nanohole periods. A maximum 5-fold photoluminescence enhancement is statistically achieved experimentally for the single quantum dots immobilized at the bottom of simulation-optimized nanoholes in comparison to those cast-deposited on bare glass substrate. Hence, boosting photoluminescence with optimized nanohole arrays holds promises for single-fluorophore-based biosensing.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-331173 (URN)10.1021/acs.jpclett.3c00468 (DOI)000939222300001 ()36847590 (PubMedID)2-s2.0-85149135539 (Scopus ID)
Note

QC 20230705

Available from: 2023-07-05 Created: 2023-07-05 Last updated: 2024-07-04Bibliographically approved
Samanta, A., Höglund, M., Samanta, P., Popov, S., Sychugov, I., Maddalena, L., . . . Berglund, L. (2022). Charge Regulated Diffusion of Silica Nanoparticles into Wood for Flame Retardant Transparent Wood. Advanced Sustainable Systems, 6(4), 2100354-2100354
Open this publication in new window or tab >>Charge Regulated Diffusion of Silica Nanoparticles into Wood for Flame Retardant Transparent Wood
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2022 (English)In: Advanced Sustainable Systems, ISSN 2366-7486, Vol. 6, no 4, p. 2100354-2100354Article in journal (Refereed) Published
Abstract [en]

The preparation of wood substrates modified by charged inorganic nanoparticles (NPs) diffusing into the internal cell wall structure is investigated for generating functional properties. The flammability problem of wood biocomposites is addressed. NPs applied from colloidal sols carry charge to stabilize them against aggregation. The influence of charge on particle diffusion and adsorption should play a role for their spatial distribution and localization in the wood substrate biocomposite. It is hypothesized that improved dispersion, infiltration, and stability of NPs into the wood structure can be achieved by charge control diffusion, also restricting NP agglomeration and limiting distribution to the wood cell wall. Cationic and anionic silica NPs of ≈30 nm are therefore allowed to diffuse into bleached wood. The influence of charge on distribution in wood is investigated as a function of initial sol concentration. Transparent wood is fabricated by in situ polymerization of a thiol­ene in the wood pore space. These biocomposites demonstrate excellent flame retardancy with self­extinguishing characteristics. The approach has potential for commercial fabrication of flame retardant transparent composites for glazing and other building applications.

Place, publisher, year, edition, pages
Wiley, 2022
National Category
Materials Chemistry
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-312505 (URN)10.1002/adsu.202100354 (DOI)000747298100001 ()2-s2.0-85123698362 (Scopus ID)
Funder
EU, European Research Council
Note

QC 20220523

Available from: 2022-05-19 Created: 2022-05-19 Last updated: 2022-09-21Bibliographically approved
Chen, H., Xu, J., Wang, Y., Wang, D., Ferrer-Espada, R., Zhou, J., . . . Yang, Z. (2022). Color-Switchable Nanosilicon Fluorescent Probes. ACS Nano, 16(9), 15450-15459
Open this publication in new window or tab >>Color-Switchable Nanosilicon Fluorescent Probes
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2022 (English)In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 16, no 9, p. 15450-15459Article in journal (Refereed) Published
Abstract [en]

Fluorescent probes are vital to cell imaging by allowing specific parts of cells to be visualized and quantified. Color-switchable probes (CSPs), with tunable emission wavelength upon contact with specific targets, are particularly powerful because they not only eliminate the need to wash away all unbound probe but also allow for internal controls of probe concentrations, thereby facilitating quantification. Several such CSPs exist and have proven very useful, but not for all key cellular targets. Here we report a pioneering CSP for in situ cell imaging using aldehyde-functionalized silicon nanocrystals (SiNCs) that switch their intrinsic photoluminescence from red to blue quickly when interacting with amino acids in live cells. Though conventional probes often work better in cell-free extracts than in live cells, the SiNCs display the opposite behavior and function well and fast in universal cell lines at 37 °C while requiring much higher temperature in extracts. Furthermore, the SiNCs only disperse in cytoplasm not nucleus, and their fluorescence intensity correlated linearly with the concentration of fed amino acids. We believe these nanosilicon probes will be promising tools to visualize distribution of amino acids and potentially quantify amino acid related processes in live cells. 

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2022
Keywords
bioimaging, color-switchable probe, nanocrystal, photoluminescence, silicon, surface chemistry, Amino acids, Cell culture, Cells, Color, Fluorescence, Nanocrystals, Probes, Silicon compounds, Amino-acids, Bio-imaging, Cell imaging, Fluorescent probes, Live cell, Nano-silicon, Silicon nanocrystals, Switchable, Tunable emissions, aldehyde, amino acid, fluorescent dye, nanoparticle, Aldehydes, Fluorescent Dyes, Nanoparticles
National Category
Cell Biology
Identifiers
urn:nbn:se:kth:diva-328120 (URN)10.1021/acsnano.2c07443 (DOI)000861080700001 ()36107985 (PubMedID)2-s2.0-85139112949 (Scopus ID)
Note

QC 20230602

Available from: 2023-06-02 Created: 2023-06-02 Last updated: 2023-06-02Bibliographically approved
Huang, J., Zhou, J., Jungstedt, E., Samanta, A., Linnros, J., Berglund, L. & Sychugov, I. (2022). Large-Area Transparent “Quantum Dot Glass” for Building-Integrated Photovoltaics. ACS Photonics, 9(7), 2499-2509
Open this publication in new window or tab >>Large-Area Transparent “Quantum Dot Glass” for Building-Integrated Photovoltaics
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2022 (English)In: ACS Photonics, E-ISSN 2330-4022, Vol. 9, no 7, p. 2499-2509Article in journal (Refereed) Published
Abstract [en]

A concept of transparent “quantum dot glass”(TQDG) is proposed for a combination of a quantum dot(QD)-based glass luminescent solar concentrator (LSC) and itsedge-attached solar cells, as a type of transparent photovoltaics(TPVs) for building-integrated photovoltaics (BIPVs). Differentfrom conventional LSCs, which typically serve as pure opticaldevices, TQDGs have to fulfill requirements as both powergeneratingcomponents and building construction materials. In thiswork, we demonstrate large-area (400 cm2) TQDGs based onsilicon QDs in a triplex glass configuration. An overall powerconversion efficiency (PCE) of 1.57% was obtained with back-reflection for a transparent TQDG (average visible transmittance of84% with a color rendering index of 88 and a low haze ≤3%), contributing to a light utilization efficiency (LUE) of 1.3%, which isamong the top reported TPVs based on the LSC technology with similar size. Most importantly, these TQDGs are shown to havebetter thermal and sound insulation properties compared to normal float glass, as well as improved mechanical performance andsafety, which significantly pushes the TPV technology toward practical building integration. TQDGs simultaneously exhibit favorablephotovoltaic, aesthetic, and building envelope characteristics and can serve as a multifunctional material for the realization of nearlyzero-energy building concepts.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2022
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-317146 (URN)10.1021/acsphotonics.2c00633 (DOI)000821927300001 ()2-s2.0-85135242257 (Scopus ID)
Funder
Swedish Energy Agency, 46360-1
Note

QC 20220906

Available from: 2022-09-06 Created: 2022-09-06 Last updated: 2022-09-27Bibliographically approved
Zhou, J., Huang, J. & Sychugov, I. (2022). Optical center of a luminescent solar concentrator. Optics Letters, 47(19), 4985
Open this publication in new window or tab >>Optical center of a luminescent solar concentrator
2022 (English)In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 47, no 19, p. 4985-Article in journal (Refereed) Published
Abstract [en]

This letter introduces a novel approach estimating the power conversion efficiency (PCE) of a square luminescent solar concentrator (LSC) by point excitations on the “optical centers” as proposed here. Predicted by theoretical calculations, photoluminescence emissions from these optical centers experience almost the same average optical path with those from the whole device under uniform illumination. This is experimentally verified by a 20 × 20 cm2 silicon quantum dots-based LSC, with a negligible error between the predicted PCE and the measured one. This method provides a convenient way to estimate the photovoltaic performance of large-area LSC devices with basic laboratory instruments.

Place, publisher, year, edition, pages
Optica Publishing Group, 2022
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-317147 (URN)10.1364/OL.467917 (DOI)000968987800006 ()36181167 (PubMedID)2-s2.0-85138788116 (Scopus ID)
Note

QC 20220912

Available from: 2022-09-06 Created: 2022-09-06 Last updated: 2025-06-16Bibliographically approved
Chen, H., Montanari, C., Shanker, R., Marcinkevičius, S., Berglund, L. & Sychugov, I. (2022). Photon Walk in Transparent Wood: Scattering and Absorption in Hierarchically Structured Materials. Advanced Optical Materials, Article ID 2102732.
Open this publication in new window or tab >>Photon Walk in Transparent Wood: Scattering and Absorption in Hierarchically Structured Materials
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2022 (English)In: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071, article id 2102732Article in journal (Refereed) Published
Abstract [en]

The optical response of hierarchical materials is convoluted, which hinders their direct study and property control. Transparent wood (TW) is an emerging biocomposite in this category, which adds optical function to the structural properties of wood. Nano- and microscale inhomogeneities in composition, structure and at interfaces strongly affect light transmission and haze. While interface manipulation can tailor TW properties, the realization of optically clear wood requires detailed understanding of light-TW interaction mechanisms. Here we show how material scattering and absorption coefficients can be extracted from a combination of experimental spectroscopic measurements and a photon diffusion model. Contributions from different length scales can thus be deciphered and quantified. It is shown that forward scattering dominates haze in TW, primarily caused by refractive index mismatch between the wood substrate and the polymer phase. Rayleigh scattering from the wood cell wall and absorption from residual lignin have minor effects on transmittance, but the former affects haze. Results provide guidance for material design of transparent hierarchical composites towards desired optical functionality; we demonstrate experimentally how transmittance and haze of TW can be controlled over a broad range.

Place, publisher, year, edition, pages
Wiley, 2022
National Category
Physical Sciences Bio Materials Composite Science and Engineering
Identifiers
urn:nbn:se:kth:diva-307402 (URN)10.1002/adom.202102732 (DOI)000769582700001 ()2-s2.0-85125315413 (Scopus ID)
Funder
EU, European Research Council, 742733Knut and Alice Wallenberg Foundation
Note

QC 20220125

Available from: 2022-01-25 Created: 2022-01-25 Last updated: 2022-09-23Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2562-0540

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