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Zhang, W., Wang, L., Guo, Y., Zhang, B., Leandri, V., Xu, B., . . . Kloo, L. (2020). Single crystal structure and opto-electronic properties of oxidized Spiro-OMeTAD. Chemical Communications, 56(10), 1589-1592
Open this publication in new window or tab >>Single crystal structure and opto-electronic properties of oxidized Spiro-OMeTAD
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2020 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 56, no 10, p. 1589-1592Article in journal (Refereed) Published
Abstract [en]

Single crystals of Spiro(TFSI)2 were grown, the optical and electronic properties were characterized and compared with neutral Spiro-OMeTAD. Density-functional theory was used to get insights into binding and band structure properties. The flat valence bands indicate a rather limited orbital overlap in Spiro(TFSI)2.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2020
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-267203 (URN)10.1039/C9CC09270F (DOI)000511328200025 ()31934696 (PubMedID)2-s2.0-85079022862 (Scopus ID)
Note

QC 20200204

Available from: 2020-02-04 Created: 2020-02-04 Last updated: 2020-02-25Bibliographically approved
Xu, B., Wrede, S., Curtze, A., Tian, L., Pati, P. B., Kloo, L., . . . Tian, H. (2019). An Indacenodithieno[3,2-b]thiophene-Based Organic Dye for Solid-State p-Type Dye-Sensitized Solar Cells. ChemSusChem, 12(14), 3243-3248
Open this publication in new window or tab >>An Indacenodithieno[3,2-b]thiophene-Based Organic Dye for Solid-State p-Type Dye-Sensitized Solar Cells
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2019 (English)In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 12, no 14, p. 3243-3248Article in journal (Refereed) Published
Abstract [en]

An indacenodithieno[3,2-b]thiophene (IDTT) unit is used as a linker moiety to design a new p-type dye-TIP-for solid-state p-type dye-sensitized solar cells. Solar cells based on the TIP dye offered an efficiency of 0.18 % with an open-circuit photovoltage of 550 mV and a short-circuit photocurrent density of 0.86 mA cm(-2), which is better than those of two reference dyes, PB6 and BH4. Charge lifetime experiments reveal that the IDTT linker-based TIP dye significantly suppresses charge recombination losses in the devices.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2019
Keywords
dye-sensitized solar cells, energy materials, p-type dye, S heterocycles, solid state
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-257576 (URN)10.1002/cssc.201901102 (DOI)000478633900003 ()31144448 (PubMedID)2-s2.0-85068094200 (Scopus ID)
Note

QC 20190920

Available from: 2019-09-20 Created: 2019-09-20 Last updated: 2019-09-20Bibliographically approved
Yao, Z., Guo, Y., Wang, L., Hao, Y., Guo, Y., Franchi, D., . . . Sun, L. (2019). Energy-Loss Reduction as a Strategy to Improve the Efficiency of Dye-Sensitized Solar Cells. SOLAR RRL, 3(10), Article ID 1900253.
Open this publication in new window or tab >>Energy-Loss Reduction as a Strategy to Improve the Efficiency of Dye-Sensitized Solar Cells
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2019 (English)In: SOLAR RRL, ISSN 2367-198X, Vol. 3, no 10, article id 1900253Article in journal (Refereed) Published
Abstract [en]

Four weak donor backbones (BT, BTP, BT2, and BT3), featuring stepwise enhanced electron-donating capacities, are designed and synthesized. The sp(3) type carbons introduced are tethered with auxiliary groups to generate a better electron-blocking stereoscopic structure. A series of NB dyes are subsequently synthesized from these central cores by end-capping a strong diphenylamine donor and a planar heterocyclic acceptor 4-(benzo[c][1,2,5]thiadiazol-4-ylethynyl)benzoic acid. The fine-tuning of steric configurations and energy levels of the resulting dye molecules reduces the energy losses significantly when applied in dye-sensitized solar cells. These devices offer one of the highest open-circuit voltages (approximate to 1.03 V) reported so far, and high power conversion efficiencies of 9.6%-12.1% using the NB dyes in combination with a well-developed cobalt-tris(4-methoxyphenyl)amine-based tandem electrolyte.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2019
Keywords
dyes, pigments, energy conversion, energy losses, solar cells
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-263353 (URN)10.1002/solr.201900253 (DOI)000490744800022 ()
Note

QC 20191119

Available from: 2019-11-19 Created: 2019-11-19 Last updated: 2019-11-19Bibliographically approved
Leandri, V., Liu, P., Sadollahkhani, A., Safdari, M., Kloo, L. & Gardner, J. M. (2019). Excited-State Dynamics of [Ru(bpy)(3)](2+) Thin Films on Sensitized TiO2 and ZrO2. ChemPhysChem, 20(4), 618-626
Open this publication in new window or tab >>Excited-State Dynamics of [Ru(bpy)(3)](2+) Thin Films on Sensitized TiO2 and ZrO2
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2019 (English)In: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 20, no 4, p. 618-626Article in journal (Refereed) Published
Abstract [en]

The excited state dynamics of Tris(2,2 '-bipyridine)ruthenium(II) hexafluorophosphate, [Ru(bpy)(3)(PF6)(2)], was investigated on the surface of bare and sensitized TiO2 and ZrO2 films. The organic dyes LEG4 and MKA253 were selected as sensitizers. A Stern-Volmer plot of LEG4-sensitized TiO2 substrates with a spin-coated [Ru(bpy)(3)(PF6)(2)] layer on top shows considerable quenching of the emission of the latter. Interestingly, time-resolved emission spectroscopy reveals the presence of a fast-decay time component (25 +/- 5 ns), which is absent when the anatase TiO2 semiconductor is replaced by ZrO2. It should be specified that the positive redox potential of the ruthenium complex prevents electron transfer from the [Ru(bpy)(3)(PF6)(2)] ground state into the oxidized sensitizer. Therefore, we speculate that the fast-decay time component observed stems from excited-state electron transfer from [Ru(bpy)(3)(PF6)(2)] to the oxidized sensitizer. Solid-state dye sensitized solar cells (ssDSSCs) employing MKA253 and LEG4 dyes, with [Ru(bpy)(3)(PF6)(2)] as a hole-transporting material (HTM), exhibit 1.2 % and 1.1 % power conversion efficiency, respectively. This result illustrates the possibility of the hypothesized excited-state electron transfer.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2019
Keywords
Excited-state electron transfer, Ru(bpy)(3), DSSCs, Photochemistry, Solid state
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-245921 (URN)10.1002/cphc.201801010 (DOI)000458952600016 ()30623544 (PubMedID)2-s2.0-85061237720 (Scopus ID)
Note

QC 20190312

Available from: 2019-03-12 Created: 2019-03-12 Last updated: 2019-12-09Bibliographically approved
Leandri, V., Pizzichetti, A. R., Xu, B., Franchi, D., Zhang, W., Benesperi, I., . . . Gardner, J. M. (2019). Exploring the Optical and Electrochemical Properties of Homoleptic versus Heteroleptic Diimine Copper(I) Complexes. Inorganic Chemistry, 58(18), 12167-12177
Open this publication in new window or tab >>Exploring the Optical and Electrochemical Properties of Homoleptic versus Heteroleptic Diimine Copper(I) Complexes
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2019 (English)In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 58, no 18, p. 12167-12177Article in journal (Refereed) Published
Abstract [en]

Due to ligand scrambling, the synthesis and investigation of the properties of heteroleptic Cu(I) complexes can be a challenging task. In this work, we have studied the optical and electrochemical properties of a series of homoleptic complexes, such as [Cu(dbda)(2)](+), [Cu(dmp)(2)](+), [Cu(Br-dmp)(2)](+), [Cu(bcp)(2)](+), [Cu(dsbtmp)(2)](+), [Cu(biq)(2)](+), and [Cu(dap)(2)](+) in solution, and those of their heteroleptics [Cu(dbda)(dmp)](+), [Cu(dbda)(Br-dmp)](+), [Cu(dbda)(bcp)](+), [Cu(dbda)(dsbtmp))(+), [Cu(dbda)(biq)](+), [Cu(dbda)(dap)](+) adsorbed on the surface of anatase TiO2 (dbda = 6,6'-dimethyl-2,2'-bipyridine-4,4'-dibenzoic acid; dmp = 2,9-dimethyl-1,10-phenanthroline; Br-dmp = 5-bromo 2,9-dimethyl-1,10-phenanthroline; bcp = bathocuproine or 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline; dsbtmp = 2,9-di(sec-butyl)-3,4,7,8-tetramethyl-1,10-phenanthroline; biq = 2,2'-biquinoline; dap = 2,9-dianisyl-1,10-phenanthroline). We show that the maximum absorption wavelengths of the heteroleptic complexes on TiO2 can be reasonably predicted from those of the homoleptic complexes in solution through a simple linear relation, whereas the prediction of their redox properties is less trivial. In the latter case, two different linear patterns emerge: one including the ligands bcp, biq, and dap and another one including the ligands dmp, Br-dmp, and dsbtmp. We offer an interpretation of the data based on the chemical structure of the ligands. On one hand, ligands bcp, biq, and dap possess a more extended pi-conjugated system, which gives a more prominent contribution to the overall redox properties of the ligand dbda. On the other hand, the ligands dmp, Br-dmp, and dsbtmp are all phenanthroline-based containing alkyl substituents and contribute less than dbda to the overall redox properties.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Inorganic Chemistry
Research subject
Chemistry
Identifiers
urn:nbn:se:kth:diva-261306 (URN)10.1021/acs.inorgchem.9b01487 (DOI)000486565600035 ()31483631 (PubMedID)2-s2.0-85072235085 (Scopus ID)
Note

QC 20191008

Available from: 2019-10-08 Created: 2019-10-08 Last updated: 2019-11-20Bibliographically approved
Wang, L., Sheibani, E., Guo, Y., Zhang, W., Li, Y., Liu, P., . . . Sun, L. (2019). Impact of Linking Topology on the Properties of Carbazole-Based Hole-Transport Materials and their Application in Solid-State Mesoscopic Solar Cells. SOLAR RRL, Article ID 1900196.
Open this publication in new window or tab >>Impact of Linking Topology on the Properties of Carbazole-Based Hole-Transport Materials and their Application in Solid-State Mesoscopic Solar Cells
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2019 (English)In: SOLAR RRL, ISSN 2367-198X, article id 1900196Article in journal (Refereed) Epub ahead of print
Abstract [en]

Carbazole is a promising core for the molecular design of hole-transport materials (HTMs) for solid-state mesoscopic solar cells (ssMSCs), such as solid-state dye-sensitized solar cells (ssDSSCs) and perovskite solar cells (PSCs) due to its low cost and excellent optoelectronic properties of its derivatives. Although carbazole-based HTMs are intensely investigated in ssMSCs and promising device performance is demonstrated, the fundamental understanding of the impact of linking topology on the properties of carbazole-based HTMs is lacking. Herein, the effect of the linking topology on the optical and electronic properties of a series of carbazole-based HTMs with 2,7-substitution and 3,6-substitution is systematically investigated. The results demonstrate that the 2,7-substituted carbazole-based HTMs display higher hole mobility and conductivity among this series of analogous molecules, thereby exhibiting better device performance. In addition, the conductivity of the HTMs is improved after light treatment, which explains the commonly observed light-soaking phenomenon of ssMSCs in general. All these carbazole-based HTMs are successfully applied in ssMSCs and one of the HTMs X50-based devices yield a promising efficiency of 6.8% and 19.2% in ssDSSCs and PSCs, respectively. This study provides guidance for the molecular design of effective carbazole-based HTMs for high-performance ssMSCs and related electronic devices.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2019
Keywords
hole-transport materials, carbazole, linking topology, mesoscopic solar cells, perovskite solar cells
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-255742 (URN)10.1002/solr.201900196 (DOI)000477425300001 ()
Note

QC 20190813

Available from: 2019-08-13 Created: 2019-08-13 Last updated: 2019-08-13Bibliographically approved
Gao, J., Yang, W., El-Zohry, A. M., Prajapati, G. K., Fang, Y., Dai, J., . . . Kloo, L. (2019). Light-induced electrolyte improvement in cobalt tris(bipyridine)-mediated dye-sensitized solar cells. Journal of Materials Chemistry A, 7(33), 19495-19505
Open this publication in new window or tab >>Light-induced electrolyte improvement in cobalt tris(bipyridine)-mediated dye-sensitized solar cells
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2019 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 33, p. 19495-19505Article in journal (Refereed) Published
Abstract [en]

Lithium-ion-free tris(2,2 '-bipyridine) Co(ii/iii)-mediated electrolytes have previously been proposed for long-term stable dye-sensitized solar cells (DSSCs). Such redox systems also offer an impressive DSSC performance improvement under light soaking exposure, manifested by an increase in photocurrent and fill factor without the expense of decreasing photovoltage. Kinetic studies show that charge transfer and ion diffusion at the electrode/electrolyte interface are improved due to the light exposure. Control experiments reveal that the light effect is unambiguously associated with electrolyte components, [Co(bpy)(3)](3+) and the Lewis-base additive tert-butylpyridine (TBP). Electrochemical and spectroscopic investigation of the [Co(bpy)(3)](3+)/TBP mixtures points out that the presence of TBP, which retards the electrolyte diffusion, however causes an irreversible redox reaction of [Co(bpy)(3)](3+) upon light exposure that improves the overall conductivity. This discovery not only provides a new strategy to mitigate the typical J(sc)-V-oc trade-off in Co(ii/iii)-mediated DSSCs but also highlights the importance of investigating the photochemistry of a photoelectrochemical system.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2019
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-259417 (URN)10.1039/c9ta07198a (DOI)000482139000027 ()2-s2.0-85071187004 (Scopus ID)
Note

QC 20190924

Available from: 2019-09-24 Created: 2019-09-24 Last updated: 2019-09-24Bibliographically approved
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: 2020-02-04Bibliographically approved
Starkholm, A., Kloo, L. & Svensson, P. H. (2019). Polyiodide Hybrid Perovskites: A Strategy To Convert Intrinsic 2D Systems into 3D Photovoltaic Materials. ACS Applied Energy Materials, 2(1), 477-485
Open this publication in new window or tab >>Polyiodide Hybrid Perovskites: A Strategy To Convert Intrinsic 2D Systems into 3D Photovoltaic Materials
2019 (English)In: ACS Applied Energy Materials, ISSN 2574-0962, Vol. 2, no 1, p. 477-485Article in journal (Refereed) Published
Abstract [en]

Two new organic inorganic hybrid perovskite compounds, (Me3S)(2)Pb5I14*2I(2) (1) and (C8H11S)(2)Pb2I6*I-2 (2), have been synthesized and subsequently characterized in this study. The materials were synthesized from facile one-pot, one-step reactions of lead iodide, corresponding sulfide, methanol, iodine, and hydroiodic acid in the case of 2. Structural analysis reveals the presence of polyiodide entities in both compounds. Compound 1 contains triiodide anions, I-3(-), that are uniquely shared between the 2D inorganic slabs, forming a 3D network. Both 1 and 2 have I-2 molecules that are bridging the inorganic slabs through a structural motif that can be regarded as a tetraiodide anion, I-4(2-). Optical spectroscopy shows band gaps of 1.86 eV for 1 and 1.89 eV for 2. The optoelectronic properties were further investigated with band structure calculations. Single-crystal IV-characteristics of 1 show that the compound is photoactive confirming it as a promising photovoltaic candidate. Compound 1 highlights a novel strategy of designing 3D semiconducting hybrid materials by incorporating polyiodides to provide direct geometric and electronic connections between the semiconducting inorganic perovskite sheets.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
organic inorganic hybrid materials, perovskites, polyiodide, solar cells, dimensionality, iodine
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-245958 (URN)10.1021/acsaem.8b01507 (DOI)000458706900060 ()
Note

QC 20190314

Available from: 2019-03-14 Created: 2019-03-14 Last updated: 2019-03-14Bibliographically approved
Trilaksana, H., Shearer, C., Kloo, L. & Andersson, G. G. (2019). Restructuring of Dye Layers in Dye Sensitized Solar Cells: Cooperative Adsorption of N719 and Chenodeoxycholic Acid on Titania. ACS Applied Energy Materials, 2(1), 124-130
Open this publication in new window or tab >>Restructuring of Dye Layers in Dye Sensitized Solar Cells: Cooperative Adsorption of N719 and Chenodeoxycholic Acid on Titania
2019 (English)In: ACS Applied Energy Materials, ISSN 2574-0962, Vol. 2, no 1, p. 124-130Article in journal (Refereed) Published
Abstract [en]

The effect of the co-adsorbent chenodeoxycholic acid (CDCA) up to a concentration of 20 mM on the adsorption of the dye N719 onto titania has been investigated using neutral impact collision ion scattering spectroscopy. It is shown that the co-adsorption of CDCA changes the adsorption mode of N719 from multilayer toward monolayer. FT-IR spectroscopy shows that the adsorption of CDCA increases with increasing CDCA concentration. In contrast, the amount of N719 adsorbed onto titania shows a minimum at 10 mM CDCA, and the relationship between the amount of CDCA and of N719 adsorbed onto titania depends nonmonotonically on the CDCA concentration. The co-adsorption of CDCA and N719 can be described as cooperative. The effect is observed for both low and high N719 concentrations.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
dye sensitized solar cells, co-adsorbent, monolayer, multilayer, concentration depth profiles, neutral impact collision ion scattering spectroscopy
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-245957 (URN)10.1021/acsaem.8b01864 (DOI)000458706900015 ()
Note

QC 20190314

Available from: 2019-03-14 Created: 2019-03-14 Last updated: 2019-03-14Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-0168-2942

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