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Eriksson, Anna
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Publications (10 of 13) Show all publications
Johansson, M. B., Edvinsson, T., Bitter, S., Eriksson, A., Johansson, E., Göthelid, M. & Boschloo, G. (2016). From Quantum Dots to Micro Crystals: Organolead TriiodidePerovskite Crystal Growth from Isopropanol Solution. ECS Journal of Solid State Science and Technology, 5(10), P614-P620
Open this publication in new window or tab >>From Quantum Dots to Micro Crystals: Organolead TriiodidePerovskite Crystal Growth from Isopropanol Solution
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2016 (English)In: ECS Journal of Solid State Science and Technology, ISSN 2162-8769, E-ISSN 2162-8777, Vol. 5, no 10, p. P614-P620Article in journal (Refereed) Published
Abstract [en]

The growth mechanism and dependence on precursor conditions are vital for creation of high quality crystalline materials in many fields. Here the growth from nano sized quantum dots to micro crystalline methyl ammonium lead tri-iodide (MAPbI(3)) perovskites prepared from isopropanol solution are reported. Isopropanol is more environmental friendly compared to the commonly used solvents DMF or DMSO, both with relatively high toxicity and the proposed method can be a useful new route to prepare hybrid perovskites. Three different molar ratios of MAPbI3 perovskite solution (MAI:PbI2 of 1: 1, 2: 1 and 0.5: 1) were applied to give insights in the crystal formation mechanism also under non-stoichiometric conditions. Perovskite crystal growth is followed by TEM. From XRD powder diffraction the lattice constants have been determined and compared with results from electron diffraction (ED). Interestingly, there seems to be an occurrence of the cubic phase besides the common tetragonal phase at room temperature.

National Category
Nano Technology
Identifiers
urn:nbn:se:uu:diva-307824 (URN)10.1149/2.0241610jss (DOI)000388868500019 ()
Available from: 2016-11-22 Created: 2016-11-22 Last updated: 2017-11-29Bibliographically approved
Eriksson K., S., Josefsson, I., Ellis, H., Amat, A., Pastore, M., Oscarsson, J., . . . Rensmo, H. (2016). Geometrical and energetical structural changes in organic dyes for dye-sensitized solar cells probed with photoelectron spectroscopy and DFT. Physical Chemistry, Chemical Physics - PCCP, 18(1), 252-260
Open this publication in new window or tab >>Geometrical and energetical structural changes in organic dyes for dye-sensitized solar cells probed with photoelectron spectroscopy and DFT
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2016 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 18, no 1, p. 252-260Article in journal (Other academic) Published
Abstract [en]

The effects of alkoxy chain length in triarylamine based donor acceptor organic dyes are investigated with respect to the electronic and molecular surface structures on the performance of solar cells and the electron lifetime. The dyes were investigated when adsorbed on TiO2 in a configuration that can be used for dye sensitized solar cells (DSCs). Specifically, the two dyes D35 and D45 were compared using photoelectron spectroscopy (PES) and density functional theory (DFT) calculations. The differences in solar cell characteristics when longer alkoxy chains are introduced in the dye donor unit are attributed to geometrical changes in dye packing while only minor differences were observed in the electronic structure. A higher dye load was observed for D45 on TiO2. However, D35 based solar cells result in higher photocurrent although the dye load is lower. This is explained by different geometrical structures of the dyes on the surface.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-230853 (URN)10.1039/c5cp04589d (DOI)000368755500027 ()
Funder
Swedish Research CouncilCarl Tryggers foundation Swedish Energy AgencyStandUp
Available from: 2014-08-31 Created: 2014-08-31 Last updated: 2017-12-05Bibliographically approved
Eriksson, S. K., Hahlin, M., Axnanda, S., Crumlin, E., Wilks, R., Odelius, M., . . . Siegbahn, H. (2016). In-Situ Probing of H2O Effects on a Ru-Complex Adsorbed on TiO2 Using Ambient Pressure Photoelectron Spectroscopy. Topics in catalysis, 59(5-7), 583-590
Open this publication in new window or tab >>In-Situ Probing of H2O Effects on a Ru-Complex Adsorbed on TiO2 Using Ambient Pressure Photoelectron Spectroscopy
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2016 (English)In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 59, no 5-7, p. 583-590Article in journal (Refereed) Published
Abstract [en]

Dye-sensitized interfaces in photocatalytic and solar cells systems are significantly affected by the choice of electrolyte solvent. In the present work, the interface between the hydrophobic Ru-complex Z907, a commonly used dye in molecular solar cells, and TiO2 was investigated with ambient pressure photoelectron spectroscopy (AP-PES) to study the effect of water atmosphere on the chemical and electronic structure of the dye/TiO2 interface. Both laboratory-based Al K alpha as well as synchrotron-based ambient pressure measurements using hard X-ray (AP-HAXPES) were used. AP-HAXPES data were collected at pressures of up to 25 mbar (i.e., the vapor pressure of water at room temperature) showing the presence of an adsorbed water overlayer on the sample surface. Adopting a quantitative AP-HAXPES analysis methodology indicates a stable stoichiometry in the presence of the water atmosphere. However, solvation effects due to the presence of water were observed both in the valence band region and for the S 1s core level and the results were compared with DFT calculations of the dye-water complex.

Keywords
Dye-sensitized solar cells, AP-HAXPES, DFT, H2O, Photoelectron spectroscopy
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-282482 (URN)10.1007/s11244-015-0533-3 (DOI)000371424800018 ()
Funder
Swedish Energy Agency, P22191-5Swedish Research Council, VR-2010-4132Swedish Research Council, VR-2014-6019Swedish Research Council, VR-2015-03956StandUpCarl Tryggers foundation , CTS 14:355VINNOVA
Available from: 2016-04-05 Created: 2016-04-05 Last updated: 2017-11-30Bibliographically approved
Oscarsson, J., Fredin, K., Ahmadi, S., Eriksson, A. I. K., Johansson, E. M. J. & Rensmo, H. (2016). Molecular degradation of D35 and K77 sensitizers when exposed to temperatures exceeding 100 °C investigated by photoelectron spectroscopy. Physical Chemistry, Chemical Physics - PCCP, 18(12), 8598-8607
Open this publication in new window or tab >>Molecular degradation of D35 and K77 sensitizers when exposed to temperatures exceeding 100 °C investigated by photoelectron spectroscopy
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2016 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 18, no 12, p. 8598-8607Article in journal (Refereed) Published
Abstract [en]

Degradation of the materials in dye-sensitized solar cells at elevated temperatures is critical for use in real applications. Both during fabrication of the solar cell and under real working conditions the solar cells will be exposed to heat. In this work, mesoporous TiO2 electrodes sensitized with the dyes D35 and K77 were subject to heat-treatment and the effects of this were thereafter investigated by photoelectron spectroscopy. For D35 it was found that heat-treatment changes the binding configuration inducing an increased interaction between the sulfur of the linker unit and the TiO2 surface. The interaction resulting from the change in binding configuration also affects the position of the HOMO level, where a shift of + 0.2 eV is observed when heated to 200 degrees C. For K77, parts of the thiocyanate units are detached and the nitrogen atom leaves the electrode whereas sulfur remains on the surface in various forms of sulfurous oxides. The total dye coverage of K77 gets reduced by heat-treatment. The HOMO level gets progressively less pronounced due to a loss of HOMO level electrons as a consequence of the lower dye coverage when heat-treated, which leads to a lower excitation rate and lower efficiency. The results are discussed in the context of performance for dye-sensitized solar cells.

National Category
Atom and Molecular Physics and Optics Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-283259 (URN)10.1039/C5CP07921G (DOI)000372249100031 ()26949128 (PubMedID)
Funder
Swedish Energy Agency, P221191-5Swedish Research Council FormasSwedish Research Council, 2014-6018, 2012-4721
Available from: 2016-04-12 Created: 2016-04-12 Last updated: 2017-11-30Bibliographically approved
Yang, W., Pazoki, M., Eriksson, A. I. K., Hao, Y. & Boschloo, G. (2015). A key discovery at the TiO2/dye/electrolyte interface: slow local charge compensation and a reversible electric field. Physical Chemistry, Chemical Physics - PCCP, 17(26), 16744-16751
Open this publication in new window or tab >>A key discovery at the TiO2/dye/electrolyte interface: slow local charge compensation and a reversible electric field
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2015 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 17, no 26, p. 16744-16751Article in journal (Refereed) Published
Abstract [en]

Dye-sensitized mesoporous TiO2 films have been widely applied in energy and environmental science related research fields. The interaction between accumulated electrons inside TiO2 and cations in the surrounding electrolyte at the TiO2/dye/electrolyte interface is, however, still poorly understood. This interaction is undoubtedly important for both device performance and fundamental understanding. In the present study, Stark effects of an organic dye, LEG4, adsorbed on TiO2 were well characterized and used as a probe to monitor the local electric field at the TiO2/dye/electrolyte interface. By using time-resolved photo- and potential-induced absorption techniques, we found evidence for a slow (t > 0.1 s) local charge compensation mechanism, which follows electron accumulation inside the mesoporous TiO2. This slow local compensation was attributed to the penetration of cations from the electrolyte into the adsorbed dye layer, leading to a more localized charge compensation of the electrons inside TiO2. Importantly, when the electrons inside TiO2 were extracted, a remarkable reversal of the surface electric field was observed for the first time, which is attributed to the penetrated and/or adsorbed cations now being charge compensated by anions in the bulk electrolyte. A cation electrosorption model is developed to account for the overall process. These findings give new insights into the mesoporous TiO2/dye/electrolyte interface and the electron-cation interaction mechanism. Electrosorbed cations are proposed to act as electrostatic trap states for electrons in the mesoporous TiO2 electrode.

National Category
Physical Sciences Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-258901 (URN)10.1039/c5cp01274k (DOI)000356874000012 ()26061451 (PubMedID)
Funder
Swedish Research Council
Available from: 2015-07-21 Created: 2015-07-21 Last updated: 2017-12-04Bibliographically approved
Eriksson, A., Edwards, K. & Agmo Hernández, V. (2015). Cooperative adsorption behavior of phosphopeptides on TiO2 leads to biased enrichment, detection and quantification. The Analyst, 140(1), 303-312
Open this publication in new window or tab >>Cooperative adsorption behavior of phosphopeptides on TiO2 leads to biased enrichment, detection and quantification
2015 (English)In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 140, no 1, p. 303-312Article in journal (Refereed) Published
Abstract [en]

The adsorption behavior of phosphopeptides onto TiO2 surfaces was studied using the quartz crystal microbalance with dissipation monitoring (QCM-D) as the main experimental technique. The main focus is the characterization of the emergence of positive cooperativity under conditions where the peptides have a positively charged C-term. It is shown that when carrying no net charge, small water-soluble peptides as a rule develop positive cooperativity. The impact of the adsorption mechanism on the outcome of TiO2 based enrichment methods was investigated with the help of matrix assisted laser desorption-ionization mass spectrometry (MALDI-MS). The data presented illustrate how the phosphopeptide profile in the enriched material may deviate from that in the native sample, as cooperative phosphopeptides are overrepresented in the former. Furthermore, commonly employed washing and elution solutions may facilitate preferential release of certain peptides, leading to further bias in the recovered sample. Taken together, the results of the present study demonstrate that thorough understanding of the mechanisms behind the adsorption of phosphopeptides on the enrichment material is necessary in order to develop reliable qualitative and quantitative methods for phosphoproteomics.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2015
National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-234196 (URN)10.1039/C4AN01580K (DOI)000345824700036 ()
Available from: 2014-10-15 Created: 2014-10-15 Last updated: 2017-12-05Bibliographically approved
Yang, W., Söderberg, M., Eriksson, A. I. K. & Boschloo, G. (2015). Efficient aqueous dye-sensitized solar cell electrolytes based on a TEMPO/TEMPO+ redox couple. RSC Advances, 5(34), 26706-26709
Open this publication in new window or tab >>Efficient aqueous dye-sensitized solar cell electrolytes based on a TEMPO/TEMPO+ redox couple
2015 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 34, p. 26706-26709Article in journal (Refereed) Published
Abstract [en]

Aqueous electrolyte-based dye-sensitized solar cells (DSSCs) have recently emerged and shown to be a promising eco-friendly photovoltaic device. In the present study, we, for the first time, have developed 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) and TEMPO+ tetrafluoroborate salt as a redox couple in an aqueous electrolyte for DSSCs. With the hydrophobic dye LEG4 as a light absorber, we have achieved a power conversion efficiency of 4.3% and a record open circuit voltage of 955 mV in the device. This is attributed to the high formal redox potential of TEMPO/TEMPO+ (0.71 V vs. NHE) in water. In addition, despite the wide use of surfactants in previous studies, we have clearly shown that the addition of surfactants to the electrolyte is detrimental to solar cell performance. Therefore, the use of surfactants in aqueous DSSC electrolytes should be avoided or used with caution.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-252057 (URN)10.1039/c5ra03248b (DOI)000351556800031 ()
Available from: 2015-04-29 Created: 2015-04-28 Last updated: 2017-12-04Bibliographically approved
Eriksson, A. I. K. (2013). Enrichment and Separation of Phosphorylated Peptides on Titanium Dioxide Surfaces: Applied and Fundamental Studies. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Enrichment and Separation of Phosphorylated Peptides on Titanium Dioxide Surfaces: Applied and Fundamental Studies
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Protein phosphorylation is a very common posttranslational modification (PTM), which lately has been found to hold the keyrole in the development of many severe diseases, including cancer. Thereby, phosphoprotein analysis tools, generally based on specific enrichment of the phosphoryl group, have been a hot topic during the last decade.

In this thesis, two new TiO2-based on-target enrichment methods are developed and presented together with enlightening fundamental results.

Evaluation of the developed methods was performed by the analysis of: custom peptides, β-casein, drinking milk, and the viral protein pIIIa. The results show that: i) by optimizing the enrichment protocol (first method), new phosphorylated peptides can be found and ii) by the addition of a separation step after the enrichment (second method), more multi-phosphorylated peptides, which usually are hard to find, could be detected. The fundamental part, on the other hand, shows that the phosphopeptide adsorption is caused by electrostatic interactions, in general follows the Langmuir model, and the affinity increases with the phosphorylation degree. Here, however, the complexity of the system was also discovered, as the adsorption mechanism was found to be affected by the amino acid sequence of the phosphopeptide.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. p. 52
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1059
Keywords
Posttranslational modification, Phosphorylation, Mass spectrometry, MALDI, Adsorption, QCM-D
National Category
Physical Chemistry
Research subject
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-204723 (URN)978-91-554-8717-1 (ISBN)
Public defence
2013-09-27, The Svedbergssalen, BMC, Husargatan 3, Uppsala, 10:00 (English)
Opponent
Supervisors
Available from: 2013-09-06 Created: 2013-08-09 Last updated: 2014-01-07
Eriksson, A., Bartsch, M., Bergquist, J., Edwards, K., Bergström Lind, S. & Agmo Hernández, V. (2013). On-target titanium dioxide-based enrichment for characterization of phosphorylations in the Adenovirus pIIIa protein. Journal of Chromatography A, 1317(SI), 105-109
Open this publication in new window or tab >>On-target titanium dioxide-based enrichment for characterization of phosphorylations in the Adenovirus pIIIa protein
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2013 (English)In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1317, no SI, p. 105-109Article in journal (Refereed) Published
Abstract [en]

A recently developed titanium dioxide (TiO2) based on-target method for phosphopeptide enrichment and matrix assisted laser desorption-ionization mass spectrometry (MALDI MS) analysis was used to investigate phosphorylations in the Adenovirus type 2 structural protein pIIIa. Lysates of purified virus particles were separated on 1-D SDS-PAGE and the band for the pIIIa protein was excised for tryptic digestion into peptides that were enriched with the on-target method. The enrichment provided by the method clearly improved the detectability of phosphorylated peptides and the results show for the first time evidence for multi-phosphorylated peptides in pIIIa. Moreover, three novel phosphorylations were identified in the protein sequence, even though the precise positions could not be determined. These results illustrate the potential of the method for the characterization of novel phosphoproteomes in biological samples of medical relevance.

Keywords
Phosphopeptide enrichment, MALDI-MS, Separation, Capsid protein precursor pIIIa, TiO2
National Category
Analytical Chemistry Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-204683 (URN)10.1016/j.chroma.2013.08.096 (DOI)000327229600012 ()
Available from: 2013-08-09 Created: 2013-08-08 Last updated: 2017-12-06Bibliographically approved
Eriksson, A., Edwards, K., Hagfeldt, A. & Agmo Hernández, V. (2013). Physicochemical Characterization of Phosphopeptide/Titanium Dioxide Interactions Employing the Quartz Crystal Microbalance Technique. Journal of Physical Chemistry B, 117(7), 2019-2025
Open this publication in new window or tab >>Physicochemical Characterization of Phosphopeptide/Titanium Dioxide Interactions Employing the Quartz Crystal Microbalance Technique
2013 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 117, no 7, p. 2019-2025Article in journal (Refereed) Published
Abstract [en]

The rapidly growing field of phosphoproteomics has led to a strong demand for procedures enabling fast and reliable isolation and enrichment of phosphorylated proteins and peptides. During the past decade, several novel phosphopeptide enrichment methods based on the affinity of phosphoryl groups for titanium dioxide (TiO2) have been developed and tested. The ultimate goal of obtaining comprehensive phosphoproteomes has, however, been found difficult to achieve and the obtained results often vary, dependent on the enrichment method and protocol used. In the present study, the physical chemistry of the phosphopeptide binding to TiO2 is investigated by means of measurements using a quartz crystal microbalance with dissipation monitoring (QCM-D). Special emphasis is put on the effect of the degree of phosphorylation of the phosphopeptide, the impact of the primary amino acid structure, and the role of electrostatic interactions. The results show that, in general, adsorption of phosphopeptides follows the Langmuir model and that the affinity for the TiO2 surface increases in a nonlinear fashion with increasing degree of phosphorylation. An exception was detected, however, where positive cooperativity between the peptides existed and the Langmuir model no longer applied. The source behind the cooperativity could be traced back to the primary amino acid structure and, more specifically, the presence of positively charged amino acids in positions that enable electrostatic interaction with phosphoryl groups on neighboring peptides. Regardless of the net peptide charge, the TiO2–phosphopeptide interaction was for all phosphopeptides investigated found to be mainly of electrostatic origin. This study highlights and explains some of the most common problems with the TiO2-based enrichment methods used today.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2013
National Category
Physical Chemistry
Research subject
Chemistry with specialization in Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-195262 (URN)10.1021/jp310161m (DOI)000315432200004 ()
Available from: 2013-02-22 Created: 2013-02-22 Last updated: 2017-12-06Bibliographically approved
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