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Karlsson, Karl MartinORCID iD iconorcid.org/0000-0003-1771-9401
Alternative names
Publications (10 of 18) Show all publications
Hao, Y., Yang, W., Karlsson, K. M., Cong, J., Wang, S., Lo, X., . . . Boschloo, G. (2018). Efficient Dye-Sensitized Solar Cells with Voltages Exceeding 1 V through Exploring Tris(4-alkoxyphenyl)amine Mediators in Combination with the Tris(bipyridine) Cobalt Redox System. ACS ENERGY LETTERS, 3(8), 1929-1937
Open this publication in new window or tab >>Efficient Dye-Sensitized Solar Cells with Voltages Exceeding 1 V through Exploring Tris(4-alkoxyphenyl)amine Mediators in Combination with the Tris(bipyridine) Cobalt Redox System
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2018 (English)In: ACS ENERGY LETTERS, ISSN 2380-8195, Vol. 3, no 8, p. 1929-1937Article in journal (Refereed) Published
Abstract [en]

Tandem redox electrolytes, prepared by the addition of a tris(p-anisyl)amine mediator into classic tris(bipyridine)cobalt-based electrolytes, demonstrate favorable electron transfer and reduced energy loss in dye-sensitized solar cells. Here, we have successfully explored three tris(4-alkoxyphenyl)-amine mediators with bulky molecular structures and generated more effective tandem redox systems. This series of tandem redox electrolytes rendered solar cells with very high photovoltages exceeding 1 V, which approaches the theoretical voltage limit of tris(bipyridine)cobalt-based electrolytes. Solar cells with power conversion efficiencies of 9.7-11.0% under 1 sun illumination were manufactured. This corresponds to an efficiency improvement of up to 50% as compared to solar cells based on pure tris(bipyridine)cobalt-based electrolytes. The photovoltage increases with increasing steric effects of the tris(4-alkoxyphenyl)amine mediators, which is attributed to a retarded recombination kinetics. These results highlight the importance of structural design for optimized charge transfer at the sensitized semiconductor/electrolyte interface and provide insights for the future development of efficient dye-sensitized solar cells.

National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-234632 (URN)10.1021/acsenergylett.8b00872 (DOI)000441852800021 ()2-s2.0-85050104939 (Scopus ID)
Funder
Swedish Energy AgencySwedish Research CouncilStiftelsen Olle Engkvist ByggmästareStandUp
Note

QC 20180912

Available from: 2018-09-12 Created: 2018-09-12 Last updated: 2018-09-12Bibliographically approved
Liu, P., Xu, B., Karlsson, K. M., Zhang, J., Vlachopoulos, N., Boschloo, G., . . . Kloo, L. (2015). The combination of a new organic D-pi-A dye with different organic hole-transport materials for efficient solid-state dye-sensitized solar cells. Journal of Materials Chemistry A, 3(8), 4420-4427
Open this publication in new window or tab >>The combination of a new organic D-pi-A dye with different organic hole-transport materials for efficient solid-state dye-sensitized solar cells
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2015 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, no 8, p. 4420-4427Article in journal (Refereed) Published
Abstract [en]

A new organic donor-pi-acceptor sensitizer MKA253 has been applied for highly efficient solid-state dye-sensitized solar cells (ssDSSCs). Using 2,2',7,7'-tetrakis(N,N-di-pi-methoxyphenyl-amine) 9,9'-spirobifluorene (Spiro-OMeTAD) as the hole transport material (HTM), an excellent power conversion efficiency of 6.1% was recorded together with a high short-circuit current of 12.4 mA cm(-2) under standard AM 1.5G illumination (100 mW cm(-2)). Different combinations of dyes and HTMs have also been investigated in the ssDSSC device. The results showed that small molecule HTM based devices suffer from comparably high electron recombination losses, thus causing low open-circuit voltage. In addition, photo-induced absorption (PIA) spectroscopy showed that the small-molecule HTMs lead to more efficient dye regeneration in comparison with Spiro-OMeTAD, despite a lower thermodynamic driving force. The results of this study also show that optimized energy levels for the dye-HTMs could be a vital factor for highly efficient ssDSSCs.

Place, publisher, year, edition, pages
RSC Publishing, 2015
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-161984 (URN)10.1039/c4ta05774k (DOI)000349667700038 ()2-s2.0-84922843906 (Scopus ID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg FoundationSwedish Energy Agency
Note

QC 20150407

Available from: 2015-04-07 Created: 2015-03-20 Last updated: 2018-02-28Bibliographically approved
Yang, L., Cappel, U. B., Unger, E. L., Karlsson, M., Karlsson, K. M., Gabrielsson, E., . . . Johansson, E. M. J. (2012). Comparing spiro-OMeTAD and P3HT hole conductors in efficient solid state dye-sensitized solar cells. Physical Chemistry, Chemical Physics - PCCP, 14(2), 779-789
Open this publication in new window or tab >>Comparing spiro-OMeTAD and P3HT hole conductors in efficient solid state dye-sensitized solar cells
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2012 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 14, no 2, p. 779-789Article in journal (Refereed) Published
Abstract [en]

Two hole conductor materials, spiro-OMeTAD and P3HT, were compared in solid-state dye-sensitized solar cells. Two organic dyes containing one anchor unit (D35) or two anchor units (M3) were used in the comparison. Absorbed photon to current conversion efficiency close to unity was obtained for the devices with spiro-OMeTAD. Energy conversion efficiencies of 4.7% and 4.9% were measured for the devices with spiro-OMeTAD and the dyes D35 and M3, respectively. For the devices using the P3HT hole conductor the results were rather different comparing the two dye molecules, with energy conversion efficiencies of 3.2% and 0.5% for D35 and M3, respectively. Photo-induced absorption measurements suggest that the regeneration of the dyes, and the polymer infiltration, is not complete using P3HT, while spiro-OMeTAD regenerates the dyes efficiently. However, the TiO(2)/D35/P3HT system shows rather high energy conversion efficiency and electrochemical oxidation of the dyes on TiO(2) indicates that D35 have a more efficient dye to dye hole conduction than M3, which thereby might explain the higher performance. The dye hole conduction may therefore be of significant importance for optimizing the energy conversion in such hybrid TiO(2)/dye/polymer systems.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-91146 (URN)10.1039/c1cp23031j (DOI)000298552800042 ()2-s2.0-83455236882 (Scopus ID)
Funder
Swedish Research Council
Note
QC 20120308Available from: 2012-03-08 Created: 2012-03-08 Last updated: 2018-04-05Bibliographically approved
Karlsson, M., Yang, L., Karlsson, M. K., Sun, L., Boschloo, G. & Hagfeldt, A. (2012). Phenoxazine dyes in solid-state dye-sensitized solar cells. Journal of Photochemistry and Photobiology A: Chemistry, 239, 55-59
Open this publication in new window or tab >>Phenoxazine dyes in solid-state dye-sensitized solar cells
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2012 (English)In: Journal of Photochemistry and Photobiology A: Chemistry, ISSN 1010-6030, E-ISSN 1873-2666, Vol. 239, p. 55-59Article in journal (Refereed) Published
Abstract [en]

Several structural modifications have been made to a sensitizer dye based on the phenoxazine core. which was tested in a solid-state dye-sensitized solar cell configuration based on the hole transporting material 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9'-spirofluorene. Light-to-power conversion efficiencies between 2.5% and 4.1% are reported herein. The difference in device performance is significantly related to the variations of dye molecular structure, with dye molecules having surface protecting alkoxy-groups yielding better solar cell devices. The phenoxazine dyes were characterized by their light harvesting capabilities and electronic properties such as electron recombination lifetime and chemical dipole moment.

Keywords
Dye-sensitized, Solar cells, Spiro-OMeTAD, Dipole, Solid-state
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-100167 (URN)10.1016/j.jphotochem.2012.04.014 (DOI)000306249700008 ()2-s2.0-84861563177 (Scopus ID)
Funder
Swedish Research Council
Note
QC 20120806Available from: 2012-08-06 Created: 2012-08-06 Last updated: 2017-12-07Bibliographically approved
Karlsson, K. M. (2011). Design, Synthesis and Properties of Organic Sensitizers for Dye Sensitized Solar Cells. (Doctoral dissertation). Stockholm: KTH Royal Institute of Technology
Open this publication in new window or tab >>Design, Synthesis and Properties of Organic Sensitizers for Dye Sensitized Solar Cells
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis gives a detailed description of the design and synthesis of new organic sensitizers for Dye sensitized Solar Cells (DSCs). It is divided in 7 chapters, where the first gives an introduction to the field of DSCs and the synthesis of organic sensitizers. Chapters 2 to 6 deal with the work of the author, starting with the first publication and the other following in chronological order. The thesis is completed with some concluding remarks (chapter 7).

The DSC is a fairly new solar cell concept, also known as the Grätzel cell, after its inventor Michael Grätzel. It uses a dye (sensitizer) to capture the incident light. The dye is chemically connected to a porous layer of a wide band-gap semiconductor. The separation of light absorption and charge separation is different from the conventional Si-based solar cells. Therefore, it does not require the very high purity materials necessary for the Si-solar cells. This opens up the possibility of easier manufacturing for future large scale production. Since the groundbreaking work reported in 1991, the interest within the field has grown rapidly. Large companies have taken up their own research and new companies have started with their focus on the DSC. So far the highest solar energy to electricity conversion efficiencies have reached ~12%.

The sensitizers in this thesis are based on triphenylamine or phenoxazine as the electron donating part in the molecule. A conjugated linker allows the electrons to flow from the donor to the acceptor, which will enable the electrons to inject into the semiconductor once they are excited. Changing the structure by introducing substituents, extending the conjugation and exchanging parts of the molecule, will influence the performance of the solar cell. By analyzing the performance, one can evaluate the importance of each component in the structure and thereby gain more insight into the complex nature of the dye sensitized solar cell.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2011. p. 80
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2011:31
Keywords
Acceptor, chromophore, donor, dye, sensitized, energy level, HOMO/LUMO, linker, phenoxazine, sensitizer, solar cell, triphenylamine
National Category
Chemical Sciences Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-33190 (URN)978-91-7415-954-7 (ISBN)
Public defence
2011-05-20, K2, Teknikringen 28, Stockholm, 10:00 (English)
Opponent
Supervisors
Note
QC 20110505Available from: 2011-05-05 Created: 2011-04-29 Last updated: 2011-09-08Bibliographically approved
Jiang, X., Karlsson, K. M., Gabrielsson, E., Johansson, E. M. J., Quintana, M., Karlsson, M., . . . Hagfeldt, A. (2011). Highly Efficient Solid-State Dye-Sensitized Solar Cells Based on Triphenylamine Dyes. Advanced Functional Materials, 21(15), 2944-2952
Open this publication in new window or tab >>Highly Efficient Solid-State Dye-Sensitized Solar Cells Based on Triphenylamine Dyes
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2011 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 21, no 15, p. 2944-2952Article in journal (Refereed) Published
Abstract [en]

Two triphenylamine-based metal-free organic sensitizers, D35 with a single anchor group and M14 with two anchor groups, have been applied in dye-sensitized solar cells (DSCs) with a solid hole transporting material or liquid iodide/triiodide based electrolyte. Using the molecular hole conductor 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenyl-amine)9,9'-spirobifluorene (spiro-OMeTAD), good overall conversion efficiencies of 4.5% for D35 and 4.4% for M14 were obtained under standard AM 1.5G illumination (100 mW cm(-2)). Although M14 has a higher molar extinction coefficient (by similar to 60%) and a slightly broader absorption spectrum compared to D35, the latter performs slightly better due to longer lifetime of electrons in the TiO(2), which can be attributed to differences in the molecular structure. In iodide/triiodide electrolyte-based DSCs, D35 outperforms M14 to a much greater extent, due to a very large increase in electron lifetime. This can be explained by both the greater blocking capability of the D35 monolayer and the smaller degree of interaction of triiodide (iodine) with D35 compared to M14. The present work gives some insight into how the molecular structure of sensitizer affects the performance in solid-state and iodide/triiodide-based DSCs.

Keywords
ORGANIC-DYE, CHARGE RECOMBINATION, SPIRO-MEOTAD, PERFORMANCE, ELECTRON, CONVERSION, TRANSPORT, QUANTIFICATION, COORDINATION, COADSORBENT
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-39518 (URN)10.1002/adfm.201002319 (DOI)000294164900018 ()2-s2.0-80051678195 (Scopus ID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg Foundation
Note

QC 20110920

Available from: 2011-09-20 Created: 2011-09-12 Last updated: 2017-12-08Bibliographically approved
Tian, H., Bora, I., Jiang, X., Gabrielsson, E., Karlsson, K. M., Hagfeldt, A. & Sun, L. (2011). Modifying organic phenoxazine dyes for efficient dye-sensitized solar cells. Journal of Materials Chemistry, 21(33), 12462-12472
Open this publication in new window or tab >>Modifying organic phenoxazine dyes for efficient dye-sensitized solar cells
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2011 (English)In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 21, no 33, p. 12462-12472Article in journal (Refereed) Published
Abstract [en]

Four organic dyes bearing the phenoxazine chromophore have been synthesized and applied in dye-sensitized solar cells (DSCs). The effect of different dye structures on the performance of the DSCs was investigated systematically with photophysical, photovoltaic as well as photoelectrochemical methods. Due to the slow recombination process between injected electrons and electrolyte, the IB3 dye with two 2,4-dibutoxyphenyl units showed the best efficiency of 7.0% under 100 mW cm(-2) light illumination in the liquid state-DSCs. Moreover, the phenoxazine dyes-based solid state-DSCs were fabricated for the first time. With the IB4 dye, a higher efficiency of 3.2% has been achieved under the same light intensity.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-38972 (URN)10.1039/c1jm12071a (DOI)000293694700046 ()2-s2.0-80051633132 (Scopus ID)
Funder
Knut and Alice Wallenberg FoundationSwedish Research Council
Available from: 2011-09-05 Created: 2011-09-05 Last updated: 2017-12-08Bibliographically approved
Karlsson, K. M., Jiang, X., Eriksson, S. K., Gabrielsson, E., Rensmo, H., Hagfeldt, A. & Sun, L. (2011). Phenoxazine Dyes for Dye-Sensitized Solar Cells: Relationship Between Molecular Structure and Electron Lifetime.. Chemistry - A European Journal, 17(23), 6415-6424
Open this publication in new window or tab >>Phenoxazine Dyes for Dye-Sensitized Solar Cells: Relationship Between Molecular Structure and Electron Lifetime.
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2011 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, no 23, p. 6415-6424Article in journal (Refereed) Published
Abstract [en]

A series of metal-free organic dyes with a core phenoxazine chromophore have been synthesized and tested as sensitizers in dye-sensitized solar cells. Overall conversion efficiencies of 6.03-7.40 % were reached under standard AM 1.5G illumination at a light intensity of 100 mW cm(-2) . A clear trend in electron lifetime could be seen; a dye with a furan-conjugated linker showed a shorter lifetime relative to dyes with the acceptor group directly attached to the phenoxazine. The addition of an extra donor unit, which bore insulating alkoxyl chains, in the 7-position of the phenoxazine could increase the lifetime even further and, together with additives in the electrolyte to raise the conduction band, an open circuit voltage of 800 mV could be achieved. From photoelectron spectroscopy and X-ray absorption spectroscopy of the dyes adsorbed on TiO(2) particles, it can be concluded that the excitation is mainly of cyano character (i.e., on average, the dye molecules are standing on, and pointing out, from the surface of TiO(2) particles).

National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-33339 (URN)10.1002/chem.201003730 (DOI)000292095800018 ()21509836 (PubMedID)2-s2.0-79958204045 (Scopus ID)
Note
Updated from submitted to published. QC 20110711Available from: 2011-05-03 Created: 2011-05-03 Last updated: 2017-12-11Bibliographically approved
Kuang, D., Comte, P., Zakeeruddin, S. M., Hagberg, D. P., Karlsson, K. M., Sun, L., . . . Grätzel, M. (2011). Stable dye-sensitized solar cells based on organic chromophores and ionic liquid electrolyte. Solar Energy, 85(6), 1189-1194
Open this publication in new window or tab >>Stable dye-sensitized solar cells based on organic chromophores and ionic liquid electrolyte
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2011 (English)In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 85, no 6, p. 1189-1194Article in journal (Refereed) Published
Abstract [en]

A series of polyene-diphenylaniline based organic dyes (coded as D5, D7, D9 and D11) have been reported for the application in ionic liquid electrolyte based dye-sensitized solar cells. The effects of substitution of organic dyes on the photovoltaic performance have been investigated, which show addition of methoxy groups on the triphenylamine donor group increases short-circuit current, open-circuit voltage and photovoltaic performance. A power conversion efficiency of 6.5% under AM 1.5 sunlight at 100 mW/cm(2) has been obtained with D11 dye in combination with a binary ionic liquid electrolyte, which when subjected to accelerated testing under one sun light soaking at 60 degrees C, the efficiency remained 90% of initial efficiency.

Keywords
Organic dye, Ionic liquid, Nanocrystalline, Dye-sensitized solar cell, Impedance
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-35599 (URN)10.1016/j.solener.2011.02.025 (DOI)000291832600004 ()2-s2.0-79956204412 (Scopus ID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg Foundation
Note
QC 20110705Available from: 2011-07-05 Created: 2011-07-04 Last updated: 2017-12-11Bibliographically approved
Marinado, T., Nonomura, K., Nissfolk, J., Karlsson, M. K., Hagberg, D. P., Sun, L., . . . Hagfeldt, A. (2010). How the Nature of Triphenylamine-Polyene Dyes in Dye-Sensitized Solar Cells Affects the Open-Circuit Voltage and Electron Lifetimes. Langmuir, 26(4), 2592-2598
Open this publication in new window or tab >>How the Nature of Triphenylamine-Polyene Dyes in Dye-Sensitized Solar Cells Affects the Open-Circuit Voltage and Electron Lifetimes
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2010 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, no 4, p. 2592-2598Article in journal (Refereed) Published
Abstract [en]

Three donor-linker-acceptor triphenylamine-based cyanoacrylic acid organic dyes used For dye-sensitized solar cells (DSCs) have been examined with respect to their effect on the open-circuit voltage (V-oc). Our previous study showed a decrease in V-oc for DSCs based oil dyes with increased molecular size (increased linker conjugation). In the present study, we investigate the origin of V-oc with respect to (i) conduction band (E-CB) positions of TiO2 and (ii) degree of recombination between electrons in TiO2 and electrolyte acceptor species at the interface. These parameters were Studied its it function of dye structure, dye load, and I-2 concentration. Two types of behavior were identified: the smaller polyene dyes show a surface-protecting effect preventing recombination upon increased dye loading, whereas the larger dyes enhance the recombination. How the different dye structures affect the recombination is discussed in terms of dye surface blocking and intermolecular interactions between dyes and electrolyte acceptor species.

Keywords
efficient molecular photovoltaics; nanocrystalline tio2 electrodes; organic-dyes; conversion-efficiency; interfacial transfer; coumarin dyes; energy-levels; performance; recombination; thiophene
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-14288 (URN)10.1021/la902897z (DOI)000274342200061 ()2-s2.0-77149163036 (Scopus ID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg Foundation
Note
QC 20110126Available from: 2010-07-30 Created: 2010-07-30 Last updated: 2017-12-12Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-1771-9401

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