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Yang, Li
Publications (10 of 29) Show all publications
Zhang, J., Xu, B., Yang, L., Ruan, C., Wang, L., Liu, P., . . . Johansson, E. (2018). The Importance of Pendant Groups on Triphenylamine-Based Hole Transport Materials for Obtaining Perovskite Solar Cells with over 20% Efficiency. Advanced Energy Materials, 18(2), Article ID 1701209.
Open this publication in new window or tab >>The Importance of Pendant Groups on Triphenylamine-Based Hole Transport Materials for Obtaining Perovskite Solar Cells with over 20% Efficiency
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2018 (English)In: Advanced Energy Materials, ISSN 1614-6832, Vol. 18, no 2, article id 1701209Article in journal (Refereed) Published
Abstract [en]

Tremendous progress has recently been achieved in the field of perovskite solar cells (PSCs) as evidenced by impressive power conversion efficiencies (PCEs); but the high PCEs of >20% in PSCs has so far been mostly achieved by using the hole transport material (HTM) spiro-OMeTAD; however, the relatively low conductivity and high cost of spiro-OMeTAD significantly limit its potential use in large-scale applications. In this work, two new organic molecules with spiro[fluorene-9,9-xanthene] (SFX)-based pendant groups, X26 and X36, have been developed as HTMs. Both X26 and X36 present facile syntheses with high yields. It is found that the introduced SFX pendant groups in triphenylamine-based molecules show significant influence on the conductivity, energy levels, and thin-film surface morphology. The use of X26 as HTM in PSCs yields a remarkable PCE of 20.2%. In addition, the X26-based devices show impressive stability maintaining a high PCE of 18.8% after 5 months of aging in controlled (20%) humidity in the dark. We believe that X26 with high device PCEs of >20% and simple synthesis show a great promise for future application in PSCs, and that it represents a useful design platform for designing new charge transport materials for optoelectronic applications.

Keywords
high efficiency, hole transport materials, perovskites, photovoltaic devices, solar cells
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-336199 (URN)10.1002/aenm.201701209 (DOI)000419864800001 ()
Funder
Swedish Energy AgencyÅForsk (Ångpanneföreningen's Foundation for Research and Development)Swedish Research CouncilSwedish Research Council Formas
Available from: 2017-12-12 Created: 2017-12-12 Last updated: 2018-02-14Bibliographically approved
Zhang, J., Hultqvist, A., Zhang, T., Jiang, L., Ruan, C., Yang, L., . . . Johansson, E. (2017). Al2O3 Underlayer Prepared by Atomic Layer Deposition for Efficient Perovskite Solar Cells.. ChemSusChem, 10(19), 3810-3817
Open this publication in new window or tab >>Al2O3 Underlayer Prepared by Atomic Layer Deposition for Efficient Perovskite Solar Cells.
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2017 (English)In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 19, p. 3810-3817Article in journal (Refereed) Published
Abstract [en]

Perovskite solar cells, as an emergent technology for solar energy conversion, have attracted much attention in the solar cell community by demonstrating impressive enhancement in power conversion efficiencies. However, the high temperature and manually processed TiO2 underlayer prepared by spray pyrolysis significantly limit the large-scale application and device reproducibility of perovskite solar cells. In this study, lowtemperature atomic layer deposition (ALD) is used to prepare a compact Al2 O3 underlayer for perovskite solar cells. The thickness of the Al2 O3 layer can be controlled well by adjusting the deposition cycles during the ALD process. An optimal Al2 O3 layer effectively blocks electron recombination at the perovskite/fluorine-doped tin oxide interface and sufficiently transports electrons through tunneling. Perovskite solar cells fabricated with an Al2 O3 layer demonstrated a highest efficiency of 16.2 % for the sample with 50 ALD cycles (ca. 5 nm), which is a significant improvement over underlayer-free PSCs, which have a maximum efficiency of 11.0 %. Detailed characterization confirms that the thickness of the Al2 O3 underlayer significantly influences the charge transfer resistance and electron recombination processes in the devices. Furthermore, this work shows the feasibility of using a high band-gap semiconductor such as Al2 O3 as the underlayer in perovskite solar cells and opens up pathways to use ALD Al2 O3 underlayers for flexible solar cells.

Keywords
atomic layer deposition, electron transport, perovskites, semiconductors, solar cells
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-336200 (URN)10.1002/cssc.201701160 (DOI)000428425000017 ()28857493 (PubMedID)
Funder
Swedish Energy AgencyÅForsk (Ångpanneföreningen's Foundation for Research and Development)Swedish Research CouncilSwedish Research Council FormasKnut and Alice Wallenberg Foundation
Available from: 2017-12-12 Created: 2017-12-12 Last updated: 2018-07-18Bibliographically approved
Araujo, R. B., Banerjee, A., Panigrahi, P., Yang, L., Sjödin, M., Strömme, M., . . . Ahuja, R. (2017). Assessing Electrochemical Properties of Polypyridine and Polythiophene for Prospective Application in Sustainable Organic Batteries. Physical Chemistry, Chemical Physics - PCCP, 19(4), 3307-3314
Open this publication in new window or tab >>Assessing Electrochemical Properties of Polypyridine and Polythiophene for Prospective Application in Sustainable Organic Batteries
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2017 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, no 4, p. 3307-3314Article in journal (Refereed) Published
Abstract [en]

Conducting polymers are being considered promising candidates for sustainable organic batteries mainly due to their fast electron transport properties and high recyclability. In this work, key properties of polythiophene and polypyridine have been assessed through a combined theoretical and experimental study focusing on such applications. A theoretical protocol has been developed to calculate redox potentials in solution within the framework of the density functional theory and using continuous solvation models. Here, the evolution of the electrochemical properties of solvated oligomers as a function of the length of the chain is analyzed and then the polymer properties are estimated via linear regressions using ordinary least square. The predicted values were verified against our electrochemical experiments. This protocol can now be employed to screen a large database of compounds in order to identify organic electrodes with superior properties.

National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-311276 (URN)10.1039/C6CP07435A (DOI)000394940400071 ()28091636 (PubMedID)
Funder
Swedish Foundation for Strategic Research Swedish Energy AgencyStandUpSwedish Research Council
Available from: 2016-12-22 Created: 2016-12-22 Last updated: 2017-10-19Bibliographically approved
Sjödin, M., Emanuelsson, R., Sterby, M., Strietzel, C., Yang, L., Huang, H., . . . Strömme, M. (2017). Conducting Redox Polymer Based Batteries. In: : . Paper presented at Organic Battery Days, Uppsala, June 8-9, 2017..
Open this publication in new window or tab >>Conducting Redox Polymer Based Batteries
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2017 (English)Conference paper, Oral presentation with published abstract (Refereed)
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-334410 (URN)
Conference
Organic Battery Days, Uppsala, June 8-9, 2017.
Available from: 2017-11-23 Created: 2017-11-23 Last updated: 2017-12-13Bibliographically approved
Yang, L., Huang, X., Mamedov, F., Zhang, P., Gogoll, A., Strömme, M. & Sjödin, M. (2017). Conducting redox polymers with non-activated charge transport properties. Physical Chemistry, Chemical Physics - PCCP, 19(36), 25052-25058
Open this publication in new window or tab >>Conducting redox polymers with non-activated charge transport properties
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2017 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, no 36, p. 25052-25058Article in journal (Refereed) Published
Abstract [en]

Non-activated charge transport has been demonstrated in terephthalate-functionalized conducting redox polymers. The transition from a temperature-activated conduction mechanism to a residual scattering mechanism was dependent on the doping level. The latter mechanism is associated with apparent negative activation barriers to charge transport and is generally found in polymer materials with a high degree of order. Crystallographic data, however, suggested a low degree of order in this polymer, indicating the existence of interconnected crystal domains in the predominantly amorphous polymer matrix through which the charge was transported. We have thus shown that the addition of bulky pendant groups to conducting polymers does not prevent efficient charge transport via the residual scattering mechanism with low barriers to charge transport.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2017
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-304625 (URN)10.1039/c7cp03939e (DOI)000411606200067 ()28879367 (PubMedID)
Funder
Swedish Research CouncilSwedish Foundation for Strategic Research Stiftelsen Olle Engkvist ByggmästareEU, Horizon 2020, 64431Swedish Energy Agency
Available from: 2016-10-06 Created: 2016-10-06 Last updated: 2018-06-04Bibliographically approved
Araujo, R. B., Banerjee, A., Panigrahi, P., Yang, L., Strömme, M., Sjödin, M., . . . Ahuja, R. (2017). Designing strategies to tune reduction potential of organic molecules for sustainable high capacity batteries application. Journal of Materials Chemistry A, 5(9), 4430-4454
Open this publication in new window or tab >>Designing strategies to tune reduction potential of organic molecules for sustainable high capacity batteries application
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2017 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 5, no 9, p. 4430-4454Article in journal (Refereed) Published
Abstract [en]

Organic compounds evolve as a promising alternative to the currently used inorganic materials in rechargeable batteries due to their low-cost, environmentally friendliness and flexibility. One of the strategies to reach acceptable energy densities and to deal with the high solubility of known organic compounds is to combine small redox active molecules, acting as capacity carrying centres, with conducting polymers. Following this strategy, it is important to achieve redox matching between the chosen molecule and the polymer backbone. Here, a synergetic approach combining theory and experiment has been employed to investigate this strategy. The framework of density functional theory connected with the reaction field method has been applied to predict the formal potential of 137 molecules and identify promising candidates for the referent application. The effects of including different ring types, e.g. fused rings or bonded rings, heteroatoms, [small pi] bonds, as well as carboxyl groups on the formal potential, has been rationalized. Finally, we have identified a number of molecules with acceptable theoretical capacities that show redox matching with thiophene-based conducting polymers which, hence, are suggested as pendent groups for the development of conducting redox polymer based electrode materials.

National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-314502 (URN)10.1039/C6TA09760J (DOI)000395926100022 ()
Funder
Swedish Foundation for Strategic Research Swedish Energy AgencyStandUpSwedish Research Council
Available from: 2017-02-02 Created: 2017-02-02 Last updated: 2017-10-19Bibliographically approved
Huang, X., Yang, L., Strömme, M., Sjödin, M. & Gogoll, A. (2016). 3-(3,4-ethylenedioxythiophene)prop-1-yne (pyEDOT): A new versatile building block for functionalized PEDOTs. In: 25th Organikerdagarna: . Paper presented at 25th Organikerdagarna, 14-17 June, Umeå, Sweden, 2016.
Open this publication in new window or tab >>3-(3,4-ethylenedioxythiophene)prop-1-yne (pyEDOT): A new versatile building block for functionalized PEDOTs
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2016 (English)In: 25th Organikerdagarna, 2016Conference paper, Poster (with or without abstract) (Refereed)
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-299596 (URN)
Conference
25th Organikerdagarna, 14-17 June, Umeå, Sweden, 2016
Available from: 2016-07-24 Created: 2016-07-24 Last updated: 2016-11-30Bibliographically approved
Huang, X., Yang, L., Emanuelsson, R., Bergquist, J., Strømme, M., Sjödin, M. & Gogoll, A. (2016). A versatile route to polythiophenes with functional pendant groups using alkyne chemistry. Beilstein Journal of Organic Chemistry, 12, 2682-2688
Open this publication in new window or tab >>A versatile route to polythiophenes with functional pendant groups using alkyne chemistry
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2016 (English)In: Beilstein Journal of Organic Chemistry, ISSN 2195-951X, E-ISSN 1860-5397, Vol. 12, p. 2682-2688Article in journal (Refereed) Published
Abstract [en]

A new versatile polythiophene building block, 3-(3,4-ethylenedioxythiophene)prop-1-yne (pyEDOT) (3), is prepared from glycidol in four steps in 28% overall yield. pyEDOT features an ethynyl group on its ethylenedioxy bridge, allowing further functionalization by alkyne chemistry. Its usefulness is demonstrated by a series of functionalized polythiophene derivatives that were obtained by pre- and post-electropolymerization transformations, provided by the synthetic ease of the Sonogashira coupling and click chemistry.

Keywords
electropolymerization, functional polymers, polythiophene, Sonogashira coupling, thiophene
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-310098 (URN)10.3762/bjoc.12.265 (DOI)000391506600001 ()
Funder
Swedish Research Council, VR 621-2011-4423 2015-4870Swedish Foundation for Strategic Research Swedish Energy Agency
Available from: 2016-12-09 Created: 2016-12-09 Last updated: 2017-11-29Bibliographically approved
Yang, L., Huang, X., Gogoll, A., Strömme, M. & Sjödin, M. (2016). Conducting Redox Polymer Based Anode Materials for High Power Electrical Energy Storage. Electrochimica Acta, 204, 270-275
Open this publication in new window or tab >>Conducting Redox Polymer Based Anode Materials for High Power Electrical Energy Storage
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2016 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 204, p. 270-275Article in journal (Refereed) Published
Abstract [en]

In this report we present the synthesis and characterization of two conducting redox polymers (CRPs) with polythiophene backbone and diethyl terephthalate pendant groups for the use as anode materials in secondary batteries. The materials show excellent rate capability allowing 301,Lm layers to be fully converted within seconds without the use of conductive additives. The high rate capability is traced to the open morphology of the materials that allows for fast ion transport, and to the mediation of electrons through the conducting polymer (CP) backbone. The requirements for the latter are i) that the redox chemistry of the pendant groups and the CP backbone overlaps and ii) that the CP conductivity is not compromised by the presence of the pendant groups. In the CRPs presented herein both these requirements are met and this is thus the first report on successful combination of the redox chemistry of organic redox molecules with the n-doping of conducting polymers.

Keywords
conducting redox polymers, terephthalates, polythiophene, n-doping
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-298055 (URN)10.1016/j.electacta.2016.03.163 (DOI)000376136700031 ()
Funder
Swedish Foundation for Strategic Research Swedish Research CouncilCarl Tryggers foundation Stiftelsen Olle Engkvist ByggmästareSwedish Energy AgencyEU, Horizon 2020, 644631
Available from: 2016-07-05 Created: 2016-06-29 Last updated: 2017-11-28Bibliographically approved
Yang, L., Huang, X., Gogoll, A., Strømme, M. & Sjödin, M. (2016). Effect of the Linker in Terephthalate-Functionalized Conducting Redox Polymers. Electrochimica Acta, 222, 149-155
Open this publication in new window or tab >>Effect of the Linker in Terephthalate-Functionalized Conducting Redox Polymers
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2016 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 222, p. 149-155Article in journal (Refereed) Published
Abstract [en]

Abstract The combination of high capacity redox active pendent groups and conducting polymers, realized in conducting redox polymers (CRPs), provides materials with high charge storage capacity that are electronically conducting which makes CRPs attractive for electrical energy storage applications. In this report, six polythiophene and poly(3,4-ethylenedioxythiophene)(PEDOT)-based CRPs with a diethyl terephthalate unit covalently bound to the polymer chain by various linkers have been synthesized and characterized electrochemically. The effects of the choice of polymer backbone and of the nature of the link on the electrochemistry, and in particular the cycling stability of these polymers, are discussed. All CRPs show both the doping of the polymer backbone as well as the redox behavior of the pendent groups and the redox potential of the pendent groups in the CRPs is close to that of corresponding monomer, indicating insignificant interaction between the pendant and the polymer backbone. While all CRPs show various degrees of charge decay upon electrochemical redox conversion, the PEDOT-based CRPs show significantly improved stability compared to the polythiophene counterparts. Moreover, we show that by the right choice of link the cycling stability of diethyl terephthalate substituted PEDOT-based CRPs can be significantly improved.

Keywords
conducting redox polymers, PEDOT, polythiophene, terephthalate
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-310464 (URN)10.1016/j.electacta.2016.10.183 (DOI)000392566200018 ()
Funder
Swedish Foundation for Strategic Research Swedish Research CouncilCarl Tryggers foundation Stiftelsen Olle Engkvist ByggmästareSwedish Energy AgencyEU, European Research Council, 644631
Available from: 2016-12-16 Created: 2016-12-16 Last updated: 2017-11-29Bibliographically approved
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