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Publications (10 of 20) Show all publications
Zhang, W., Sadollahkhani, A., Li, Y., Leandri, V., Gardner, J. M. & Kloo, L. (2019). Mechanistic Insights from Functional Group Exchange Surface Passivation: A Combined Theoretical and Experimental Study. ACS APPLIED ENERGY MATERIALS, 2(4), 2723-2733
Open this publication in new window or tab >>Mechanistic Insights from Functional Group Exchange Surface Passivation: A Combined Theoretical and Experimental Study
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2019 (English)In: ACS APPLIED ENERGY MATERIALS, ISSN 2574-0962, Vol. 2, no 4, p. 2723-2733Article in journal (Refereed) Published
Abstract [en]

Four different functional groups including amino (-NH2), phosphine (-PH2), hydroxyl (-OH), and thiol (-SH) were combined with POSS (polyhedral oligomeric silsesquioxane) molecules to investigate how functional groups affect the surface passivation of POSS systems. Results from density-functional theory (DFT) calculations indicate that functional group amino (-NH2) with adsorption energy 86 (56) kJ mol(-1) is consistently better than that of thiol (-SH) with adsorption energy 68 (43) kJ mor(-1) for different passivation mechanisms. Theoretical studies on the analogous POSS-OH and POSS-PH2 systems show similar adsorption energies. Two of the systems were also investigated experimentally; aminopropyl isobutyl POSS (POSS-NH2) and mercaptopropyl isobutyl POSS (POSS-SH) were applied as passivation materials for MAPbI(3) (MA = methylammonium) perovskite and (FA)(0.85)(MA)(0.15)Pb(I-3)(0.85)(Br-3)(0)(.15)(FA = formamidinium) perovskite films. The same conclusion was drawn based on the results from contact angle studies, X-ray diffraction (XRD), and the stability of solar cells in ambient atmosphere, indicating the vital importance of choice of functional groups for passivation of the perovskite materials.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
Keywords
perovskite solar cells, polyhedral oligomeric silsesquioxane (POSS), passivation, DFT calculation, stability
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:kth:diva-251284 (URN)10.1021/acsaem.9b00050 (DOI)000465644600047 ()
Note

QC 20190517

Available from: 2019-05-17 Created: 2019-05-17 Last updated: 2019-05-17Bibliographically approved
Li, Y., Cheng, M., Jungstedt, E., Xu, B., Sun, L. & Berglund, L. (2019). Optically Transparent Wood Substrate for Perovskite Solar Cells. ACS Sustainable Chemistry and Engineering, 7(6), 6061-6067
Open this publication in new window or tab >>Optically Transparent Wood Substrate for Perovskite Solar Cells
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2019 (English)In: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 7, no 6, p. 6061-6067Article in journal (Refereed) Published
Abstract [en]

Transparent wood is a candidate for use as an energy-saving building material due to its low density (ca. 1.2 g/cm(3)), high optical transmittance (over 85% at 1 mm thickness), low thermal conductivity (0.23 W m(-1) K-1), and good load-bearing performance with tough failure behavior (no shattering). High optical transmittance also makes transparent wood a candidate for optoelectronic devices. In this work, for the first time, perovskite solar cells processed at low temperature (<150 degrees C) were successfully assembled directly on transparent wood substrates. A power conversion efficiency up to 16.8% was obtained. The technologies demonstrated may pave the way for integration of solar cells with light transmitting wood building structures for energy-saving purposes.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
Biocomposite, Perovskite solar cell, Energy-Efficient, Building material, Transparent wood, Mechanical properties
National Category
Composite Science and Engineering
Identifiers
urn:nbn:se:kth:diva-248333 (URN)10.1021/acssuschemeng.8b06248 (DOI)000461978200051 ()30918764 (PubMedID)2-s2.0-85063061391 (Scopus ID)
Note

QC 20190410

Available from: 2019-04-10 Created: 2019-04-10 Last updated: 2019-04-10Bibliographically approved
Koivurova, M., Vasileva, E., Li, Y., Berglund, L. & Popov, S. (2018). Complete spatial coherence characterization of quasi-random laser emission from dye doped transparent wood. Optics Express, 26(10), 13474-13482
Open this publication in new window or tab >>Complete spatial coherence characterization of quasi-random laser emission from dye doped transparent wood
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2018 (English)In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 26, no 10, p. 13474-13482Article in journal (Refereed) Published
Abstract [en]

We report on the experimental determination of the complete two coordinate spatial coherence function of light emitted by a quasi-random laser, implemented on recently introduced dye-doped transparent wood. The spatial coherence was measured by means of a double grating interferometer, which has some advantages over the standard Young's interferometer. Analysis of the spatial coherence reveals that emission from such a material can be considered as a superposition of several spatial modes produced by individual emitters within semi-ordered scattering medium. The overall degree of coherence, (gamma)over-bar, for this quasi-random laser was found to be 0.16 +/- 0.01, having possible applications in speckle free laser imaging and illumination.

Place, publisher, year, edition, pages
OPTICAL SOC AMER, 2018
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-231223 (URN)10.1364/OE.26.013474 (DOI)000432457600117 ()29801372 (PubMedID)2-s2.0-85047074022 (Scopus ID)
Note

QC 20180628

Available from: 2018-06-28 Created: 2018-06-28 Last updated: 2018-11-26Bibliographically approved
Hua, Y., Liu, P., Li, Y., Sun, L. & Kloo, L. (2018). Composite Hole-Transport Materials Based on a Metal-Organic Copper Complex and Spiro-OMeTAD for Efficient Perovskite Solar Cells. SOLAR RRL, 2(5), Article ID UNSP 1700073.
Open this publication in new window or tab >>Composite Hole-Transport Materials Based on a Metal-Organic Copper Complex and Spiro-OMeTAD for Efficient Perovskite Solar Cells
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2018 (English)In: SOLAR RRL, ISSN 2367-198X, Vol. 2, no 5, article id UNSP 1700073Article in journal (Refereed) Published
Abstract [en]

Spiro-OMeTAD has been the most commonly used hole-transport material in perovskite solar cells. However, this material shows intrinisic drawbacks, such as low hole mobility and conductivity in its pristine form, as well as self-aggregation when deposited as thin film. These are not beneficial properties for efficient hole transport and extraction. In order to address these issues, we have designed a new type of composite hole-transport materials based on a new metal-organic copper complex (CuH) and Spiro-OMeTAD. The incorporation of the molecularly bulky HTM CuH into the Spiro-OMeTAD material efficiently improves the hole mobility and suppresses the aggregation in the Spiro-OMeTAD film. As a result, the conversion efficiencies obtained for perovskite solar cells based on the composite HTM system reached as high as 18.83%, which is superior to solar cells based on the individual hole-transport materials CuH (15.75%) or Spiro-OMeTAD (14.47%) under the same working conditions. These results show that composite HTM systems may constitute an effective strategy to further improve the efficiency of perovskite solar cells.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2018
Keywords
Hole transport materials, mobility, perovskite solar cells, small molecules
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-228439 (URN)10.1002/solr.201700073 (DOI)000432036200001 ()
Note

QC 20180529

Available from: 2018-05-29 Created: 2018-05-29 Last updated: 2018-05-29Bibliographically approved
Xu, P., Liu, P., Li, Y., Xu, B., Kloo, L., Sun, L. & Hua, Y. (2018). D-A-D-Typed Hole Transport Materials for Efficient Perovskite Solar Cells: Tuning Photovoltaic Properties via the Acceptor Group. ACS Applied Materials and Interfaces, 10(23), 19697-19703
Open this publication in new window or tab >>D-A-D-Typed Hole Transport Materials for Efficient Perovskite Solar Cells: Tuning Photovoltaic Properties via the Acceptor Group
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2018 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 23, p. 19697-19703Article in journal (Refereed) Published
Abstract [en]

Two D-A-D-structured hole-transport materials (YN1 and YN2) have been synthesized and used in perovskite solar cells. The two HTMs have low-lying HOMO levels and impressive mobility. Perovskite-based solar cells (PSCs) fabricated with YN2 showed a power conversion efficiency (PCE) value of 19.27% in ambient air, which is significantly higher than that of Spiro-OMeTAD (17.80%). PSCs based on YN1 showed an inferior PCE of 16.03%. We found that the incorporation of the stronger electron-withdrawing group in the HTM YN2 improves the PCE of PSCs. Furthermore, the YN2-based PSCs exhibit good long-term stability retaining 91.3% of its initial efficiency, whereas PSCs based on Spiro-OMeTAD retained only 42.2% after 1000 h lifetime (dark conditions). These promising results can provide a new strategy for the design of D-A-D HTMs for PSC applications in future.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
acceptor, hole-transport material, mobility, perovskite solar cells, spiro-OMeTAD
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-238197 (URN)10.1021/acsami.8b04003 (DOI)000435525100045 ()29785846 (PubMedID)2-s2.0-85047487298 (Scopus ID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg FoundationSwedish Energy Agency
Note

QC 20181119

Available from: 2018-11-19 Created: 2018-11-19 Last updated: 2018-11-19Bibliographically approved
Wang, L., Zhang, J., Liu, P., Xu, B., Zhang, B., Chen, H., . . . Sun, L. (2018). Design and synthesis of dopant-free organic hole-transport materials for perovskite solar cells. Chemical Communications, 54(69)
Open this publication in new window or tab >>Design and synthesis of dopant-free organic hole-transport materials for perovskite solar cells
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2018 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 54, no 69Article in journal (Refereed) Published
Abstract [en]

Two novel dopant-free hole-transport materials (HTMs) with spiro[dibenzo[c,h]xanthene-7,9-fluorene] (SDBXF) skeletons were prepared via facile synthesis routes. A power conversion efficiency of 15.9% in perovskite solar cells is attained by using one HTM without dopants, which is much higher than undoped Spiro-OMeTAD-based devices (10.8%). The crystal structures of both new HTMs were systematically investigated to reveal the reasons behind such differences in performance and to indicate the design principles of more advanced HTMs.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2018
National Category
Textile, Rubber and Polymeric Materials
Identifiers
urn:nbn:se:kth:diva-234569 (URN)10.1039/c8cc04026e (DOI)000442605100002 ()30043013 (PubMedID)2-s2.0-85052539543 (Scopus ID)
Funder
Swedish Energy Agency
Note

QC 20180917

Available from: 2018-09-17 Created: 2018-09-17 Last updated: 2018-10-19Bibliographically approved
Vasileva, E., Chen, H., Li, Y., Sychugov, I., Yan, M., Berglund, L. & Popov, S. (2018). Light Scattering by Structurally Anisotropic Media: A Benchmark with Transparent Wood. Advanced Optical Materials, 6(23), Article ID 1800999.
Open this publication in new window or tab >>Light Scattering by Structurally Anisotropic Media: A Benchmark with Transparent Wood
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2018 (English)In: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071, Vol. 6, no 23, article id 1800999Article in journal (Refereed) Published
Abstract [en]

Transparent wood (TW) is a biocomposite material with hierarchical structure, which exhibits high optical transmittance and anisotropic light scattering. Here, the relation between anisotropic scattering and the internal structure of transparent wood is experimentally studied and the dependence of scattering anisotropy on material thickness, which characterizes the fraction of ballistic photons in the propagating light, is shown. The limitations of the conven-tional haze, as it is implemented to isotropic materials, are discussed, and a modified characteristic parameter of light scattering—the degree of aniso-tropic scattering is defined. This parameter together with the transport mean free path value is more practical and convenient for characterization of the material scattering properties. It is believed that the generic routine described in this paper can be applied for scattering characterization and comparison of other TW materials of either different thickness, optical quality or based on various wood species.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
Keywords
anisotropic scattering, biocomposites, hierarchical structure, nanocellulose, transparent wood
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-239314 (URN)10.1002/adom.201800999 (DOI)000453512700015 ()2-s2.0-85055276864 (Scopus ID)
Funder
EU, Horizon 2020, 742733Swedish Research Council, 621-2012-4421Knut and Alice Wallenberg Foundation
Note

QC 20181126

Available from: 2018-11-20 Created: 2018-11-20 Last updated: 2019-01-16Bibliographically approved
Berglund, L., Li, Y., Fu, Q., Popov, S., Sychugov, I. & Yang, M. (2018). Modification of transparent wood for photonics functions. Paper presented at 255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA. Abstract of Papers of the American Chemical Society, 255
Open this publication in new window or tab >>Modification of transparent wood for photonics functions
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2018 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-240156 (URN)000435537702571 ()
Conference
255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA
Note

QC 20181218

Available from: 2018-12-18 Created: 2018-12-18 Last updated: 2018-12-18Bibliographically approved
Li, Y., Vasileva, E., Sychugov, I., Popov, S. & Berglund, L. (2018). Optically Transparent Wood: Recent Progress, Opportunities, and Challenges. Advanced Optical Materials, 6(14), Article ID 1800059.
Open this publication in new window or tab >>Optically Transparent Wood: Recent Progress, Opportunities, and Challenges
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2018 (English)In: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071, Vol. 6, no 14, article id 1800059Article, review/survey (Refereed) Published
Abstract [en]

Transparent wood is an emerging load-bearing material reinvented from natural wood scaffolds with added light management functionalities. Such material shows promising properties for buildings and related structural applications, including its renewable and abundant origin, interesting optical properties, outstanding mechanical performance, low density, low thermal conductivity, and great potential for multifunctionalization. In this study, a detailed summary of recent progress on the transparent wood research topic is presented. Remaining questions and challenges related to transparent wood preparation, optical property measurements, and transparent wood modification and applications are discussed.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2018
Keywords
biocomposites, optical property measurement, photonic devices, smart buildings, transparent wood, wood modification
National Category
Composite Science and Engineering
Identifiers
urn:nbn:se:kth:diva-232765 (URN)10.1002/adom.201800059 (DOI)000439490700008 ()2-s2.0-85046829217 (Scopus ID)
Funder
EU, European Research Council, 742733Swedish Research Council, 621-2012-4421
Note

QC 20180802

Available from: 2018-08-02 Created: 2018-08-02 Last updated: 2018-11-26Bibliographically approved
Popov, S., Marinins, A., Sychugov, I., Yan, M., Vasileva, E., Li, Y., . . . Ozolins, O. (2018). Polymer photonics and nano-materials for optical communication. In: 2018 17TH WORKSHOP ON INFORMATION OPTICS (WIO): . Paper presented at 17th Workshop on Information Optics (WIO), JUL 16-19, 2018, Quebec, CANADA. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Polymer photonics and nano-materials for optical communication
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2018 (English)In: 2018 17TH WORKSHOP ON INFORMATION OPTICS (WIO), Institute of Electrical and Electronics Engineers (IEEE), 2018Conference paper, Published paper (Refereed)
Abstract [en]

Polymer materials offer process compatibility, design flexibility, and low cost technology as a multi-functional platform for optical communication and photonics applications. Design and thermal reflowing technology of low loss polymer waveguides, as well as demonstration of transparent wood laser are presented in this paper.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
Series
Workshop on Information Optics, ISSN 2472-159X
Keywords
polymers, photonics, communication, wood, lasers
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-249907 (URN)000462765500008 ()978-1-5386-6013-3 (ISBN)
Conference
17th Workshop on Information Optics (WIO), JUL 16-19, 2018, Quebec, CANADA
Note

QC 20190503

Available from: 2019-05-03 Created: 2019-05-03 Last updated: 2019-05-03Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1591-5815

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