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  • 1.
    Changqing, Ruan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Maria, Strømme
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Jonas, Lindh
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    A green and simple method for preparation of an efficient palladium adsorbent based on 2,3-dialdehyde cellulose2015Conference paper (Refereed)
    Abstract [en]

    An efficient and green palladium adsorbent was prepared from 2,3-dialdehyde cellulose by reductive amination with a palladium chelating ligand in a facile one-pot procedure, and adsorption properties for palladium including adsorption isotherm, kinetics, desorption and recycling of the adsorbent obtained were studied. The successful reductive amination with the ligand and 2,3-dialdehyde cellulose was verified by FT-IR and XPS, and the adsorbent was characterized by SEM, XRD, gas adsorption and TGA. The adsorbent has a high adsorption capacity and enables fast adsorption of palladium from solution. Adsorbent materials suitable for both filters and column matrixes could be obtained.

  • 2.
    Changqing, Ruan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Maria, Strømme
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Jonas, Lindh
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Selective C6 Oxidation of Cellulose with Oxone in Water2016Conference paper (Refereed)
    Abstract [en]

    A novel method for selective C6 primary alcohol oxidation of cellulose, as an alternative to TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl), was developed. Cellulose pulp and Cladophora nanocellulose were selectively oxidized in a one-pot procedure by Oxone (2KHSO5·KHSO4·K2SO4) and efficient reaction conditions were investigated. The effects of the reactions on the morphology, viscosity and chemical structure of the products obtained were studied. The C6 primary alcohol groups were selectively oxidized to carboxyl groups, as testified by solid-state CP/MAS 13C NMR and FTIR, and the content of carboxyl groups was determined by conductometric titration. SEM, capillary-type viscometry and XRD were applied to characterize the products and to investigate the influence of the oxidation. For the first time, low-cost and stable Oxone was used as a single oxidant to oxidize cellulose into C6-carboxyl cellulose. The oxidation is an inexpensive and convenient process to produce carboxylic groups on the surface of the cellulose fibers and to make the cellulose fibers charged. Particularly, this method can avoid the use of halogens and toxic radicals and constitute a green route to access C6-carboxyl cellulose. Further, sodium bromide could be used as a co-oxidant to Oxone and increase carboxylic acid content by 10% to 20%. The Oxone oxidation is a promising alternative to the frequently employed TEMPO-mediated oxidation of cellulose, which might increase the possibility to develop and improve applications of cellulose.

  • 3.
    Changqing, Ruan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    A green and simple method for preparation of an efficient palladium adsorbent based on cysteine functionalized2,3-dialdehyde cellulose2016In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, no 4, p. 2627-2638Article in journal (Refereed)
    Abstract [en]

    A green and efficient adsorbent for adsorption of palladium ions was prepared from 2,3-dialdehyde cellulose (DAC) originating from nanocellulose from the green algae Cladophora. The DAC was functionalized with cysteine via reductive amination in a convenient one-pot procedure to provide the adsorbent. The adsorption properties for adsorbing palladium(II) ions, including capacity, adsorption isotherm and kinetics, were studied. The successful reductive amination of cysteine with 2,3-dialdehyde cellulose was confirmed by FT-IR, elemental analysis and XPS. The adsorbent was characterized by SEM, XRD, gas adsorption and TGA. The adsorbent had a high adsorption capacity (130 mg palladium per gram adsorbent) and enabled fast adsorption of palladium(II) ions from solution (80 % of maximum capacity reached in 2 h). Adsorbent materials suitable for both filters (fibrous) and column matrixes (spherical particles) could be obtained in an efficient manner by controlling the degree of oxidation while producing the DAC material.

    Download full text (pdf)
    A green and simple method for preparation of an efficient palladium adsorbent based on cysteine functionalized 2,3-dialdehyde cellulose
  • 4.
    Lindh, Jonas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Hua, Kai
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ruan, Changqing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Rocha, Igor
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Carlsson, Daniel Otto
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ferraz, Natalia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Chemical Modifications of Nanocellulose2014In: NFM conference, Prague 16-18th June 2014., 2014Conference paper (Refereed)
  • 5.
    Lindh, Jonas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ruan, Changqing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Maria, Strømme
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Preparation of Porous Cellulose Beads via Introduction of Diamine Spacers2016In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 32, no 22, p. 5600-5607Article in journal (Refereed)
    Abstract [en]

    The current work presents a synthesis route based on the reductive amination of 2,3-dialdehyde cellulose beads with diamines to render micrometer-sized beads with increased specific surface area (SSA) and porosity in the mesoporous range. Specifically, the influence of the reductive amination of 2,3-dialdehyde cellulose (DAC) using aliphatic and aromatic tethered mono- and diamines on bead microstructure was investigated. Aliphatic and aromatic tethered monoamines were found to have limited utility for producing porous beads whereas the introduction of diamines provided beads with a porous texture and an SSA increasing from <1 to >30 m(2)/g. Both aliphatic and aromatic diamines were found to be useful in producing porous beads having a pore size distribution range of 10 to 100 nm, as verified by N-2 gas adsorption and mercury intrusion porosimetry analyses. The true density of the functionalized DAC beads decreased to an average of about 1.36 g/cm(3) as compared to 1.48 g/cm(3) for the unfunctionalized, fully oxidized DAC beads. The total porosity of the beads was, according to mercury porosimetry, in the range of 54-64%. Reductive amination with 1,7-diaminoheptane provided beads that were stable under alkaline conditions (I M NaOH). It was concluded that the introduction of tethered diamines into DAC beads is a facile method for producing mesoporous beads.

  • 6.
    Ruan, Chang-Qing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Functionalization, Characterization and Applications of Oxidized Nanocellulose Derivatives2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Cellulose, a sustainable raw material derived from nature, can be used for various applications following its functionalization and oxidation. Nanocellulose, inheriting the properties of cellulose, can offer new properties due to nanoscale effects, in terms of high specific surface area and porosity. The oxidation of cellulose can provide more active sites on the cellulose chains, improving its functionalization and broadening applications. Two kinds of oxidation and their corresponding applications are described in this thesis: periodate oxidation and Oxone® oxidation.

    2,3-dialdehyde cellulose (DAC) beads were prepared from Cladophora nanocellulose via periodate oxidation, and were further modified with amines via reductive amination. Several diamines were selected as possible crosslinkers to produce porous DAC beads, which showed higher porosity, stability in alkaline solution and enhanced thermal stability.

    After functionalization of DAC beads with L-cysteine (DAC-LC), thiol, amine and carboxyl groups were introduced into the DAC beads, endowing the DAC-LC beads with high adsorption capacity for palladium. The synthesized DAC-LC beads were character­ized with SEM, FTIR, XPS, TGA, BET and XRD and the palladium adsorption process was investigated.

    Chitosan was employed as a crosslinker in functionalization of DAC beads (DAC-CS). The conditions for the synthesis of DAC-CS beads were screened and verifying the stability of the beads in alkaline solution. The DAC-CS beads produced were investigated using SEM, FTIR, XPS, TGA and BET, and the adsorption and desorption capacity of Congo red was studied, indicating DAC-CS beads have potential as sorbent.

    Oxone oxidation of cellulose is a novel one-pot oxidation method in which mainly the hydroxyl groups on C6 are oxidized to produce carboxylic acid groups on the cellulose chains. To increase the efficiency of Oxone oxidation, several reaction parameters were studied. Cellulose pulp and Cladophora nanocellulose were chosen as prototypes to investigate the effects of oxidation, and the physico­chemical properties of the oxidized products were characterized. Cellulose pulp, pretreated with Oxone oxidation, was disintegrated by homogenization to prepare cellulose nanofibers (CNF). The effect of pre­treat­ment on the preparation of CNF was studied, and the results indicated that Oxone oxidation was efficient in the production of CNF.

    List of papers
    1. Preparation of Porous Cellulose Beads via Introduction of Diamine Spacers
    Open this publication in new window or tab >>Preparation of Porous Cellulose Beads via Introduction of Diamine Spacers
    2016 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 32, no 22, p. 5600-5607Article in journal (Refereed) Published
    Abstract [en]

    The current work presents a synthesis route based on the reductive amination of 2,3-dialdehyde cellulose beads with diamines to render micrometer-sized beads with increased specific surface area (SSA) and porosity in the mesoporous range. Specifically, the influence of the reductive amination of 2,3-dialdehyde cellulose (DAC) using aliphatic and aromatic tethered mono- and diamines on bead microstructure was investigated. Aliphatic and aromatic tethered monoamines were found to have limited utility for producing porous beads whereas the introduction of diamines provided beads with a porous texture and an SSA increasing from <1 to >30 m(2)/g. Both aliphatic and aromatic diamines were found to be useful in producing porous beads having a pore size distribution range of 10 to 100 nm, as verified by N-2 gas adsorption and mercury intrusion porosimetry analyses. The true density of the functionalized DAC beads decreased to an average of about 1.36 g/cm(3) as compared to 1.48 g/cm(3) for the unfunctionalized, fully oxidized DAC beads. The total porosity of the beads was, according to mercury porosimetry, in the range of 54-64%. Reductive amination with 1,7-diaminoheptane provided beads that were stable under alkaline conditions (I M NaOH). It was concluded that the introduction of tethered diamines into DAC beads is a facile method for producing mesoporous beads.

    National Category
    Nano Technology Materials Engineering
    Identifiers
    urn:nbn:se:uu:diva-299045 (URN)10.1021/acs.langmuir.6b01288 (DOI)000377631300017 ()27181427 (PubMedID)
    Funder
    Knut and Alice Wallenberg FoundationGöran Gustafsson Foundation for promotion of scientific research at Uppala University and Royal Institute of Technology
    Available from: 2016-07-13 Created: 2016-07-13 Last updated: 2017-08-23Bibliographically approved
    2. A green and simple method for preparation of an efficient palladium adsorbent based on cysteine functionalized2,3-dialdehyde cellulose
    Open this publication in new window or tab >>A green and simple method for preparation of an efficient palladium adsorbent based on cysteine functionalized2,3-dialdehyde cellulose
    2016 (English)In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, no 4, p. 2627-2638Article in journal (Refereed) Published
    Abstract [en]

    A green and efficient adsorbent for adsorption of palladium ions was prepared from 2,3-dialdehyde cellulose (DAC) originating from nanocellulose from the green algae Cladophora. The DAC was functionalized with cysteine via reductive amination in a convenient one-pot procedure to provide the adsorbent. The adsorption properties for adsorbing palladium(II) ions, including capacity, adsorption isotherm and kinetics, were studied. The successful reductive amination of cysteine with 2,3-dialdehyde cellulose was confirmed by FT-IR, elemental analysis and XPS. The adsorbent was characterized by SEM, XRD, gas adsorption and TGA. The adsorbent had a high adsorption capacity (130 mg palladium per gram adsorbent) and enabled fast adsorption of palladium(II) ions from solution (80 % of maximum capacity reached in 2 h). Adsorbent materials suitable for both filters (fibrous) and column matrixes (spherical particles) could be obtained in an efficient manner by controlling the degree of oxidation while producing the DAC material.

    Keywords
    2, 3-dialdehyde cellulose, Palladium adsorption, Cellulose beads, Nanocellulose
    National Category
    Nano Technology
    Identifiers
    urn:nbn:se:uu:diva-303299 (URN)10.1007/s10570-016-0976-0 (DOI)000380089300028 ()
    Available from: 2016-09-15 Created: 2016-09-15 Last updated: 2017-08-23Bibliographically approved
    3. On the preparation of porous 2,3-dialdehyde cellulose beads crosslinked with chitosan and their adsorption of Congo red
    Open this publication in new window or tab >>On the preparation of porous 2,3-dialdehyde cellulose beads crosslinked with chitosan and their adsorption of Congo red
    2017 (English)In: Article in journal (Refereed) Submitted
    National Category
    Nano Technology
    Identifiers
    urn:nbn:se:uu:diva-328386 (URN)
    Available from: 2017-08-22 Created: 2017-08-22 Last updated: 2017-10-13
    4. Favored Surface-limited Oxidation of Cellulose with Oxone® in Water
    Open this publication in new window or tab >>Favored Surface-limited Oxidation of Cellulose with Oxone® in Water
    2017 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 64, p. 40600-40607Article in journal (Refereed) Published
    Abstract [en]

    A novel method for favored primary alcohol oxidation of cellulose was developed. Cellulose pulp andCladophora nanocellulose were oxidized in a one-pot procedure by Oxone® (2KHSO5$KHSO4$K2SO4)and efficient reaction conditions were identified. The effects of the reaction on the morphology,viscosity and chemical structure of the products obtained were studied. The primary alcohol groupswere oxidized to carboxyl groups and the content of carboxyl groups was determined byconductometric titration. SEM, capillary-type viscometry and XRD were applied to characterize theproducts and to investigate the influence of oxidation. For the first time, low-cost and stable Oxone®was used as a single oxidant to oxidize cellulose into carboxyl cellulose. The oxidation is an inexpensiveand convenient process to produce carboxylic groups on the surface of the cellulose fibers and to makethe cellulose fibers charged. Particularly, this method can avoid the use of halogens and potentially toxicradicals and constitute a green route to access carboxylated cellulose. Further, sodium bromide could beused as a co-oxidant to the Oxone® and increase the carboxylic acid content by 10–20%. The Oxone®oxidation is a promising method for oxidation of cellulose and might facilitate the production of CNC.

    Keywords
    Cellulose, Oxone, Tempo-Mediated Oxidation, 2, 3-Dialdehyde Cellulose, Periodate-Oxidation, Chemistry, Efficient, Bromide, Delignification, Nanocellulose, Transparent, Nanofibers
    National Category
    Nano Technology
    Research subject
    Engineering Science with specialization in Nanotechnology and Functional Materials
    Identifiers
    urn:nbn:se:uu:diva-328237 (URN)10.1039/c7ra06141b (DOI)000408043100065 ()
    Funder
    Knut and Alice Wallenberg Foundation
    Available from: 2017-08-21 Created: 2017-08-21 Last updated: 2020-01-29Bibliographically approved
    5. Cellulose nanofibers prepared via pretreatment based on Oxone® oxidation
    Open this publication in new window or tab >>Cellulose nanofibers prepared via pretreatment based on Oxone® oxidation
    Show others...
    2017 (English)In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 22, no 12, article id 2177Article in journal (Refereed) Published
    Abstract [sv]

    Softwood sulfite bleached cellulose pulp was oxidized with Oxone (R) and cellulose nanofibers (CNF) were produced after mechanical treatment with a high-shear homogenizer. UV-vis transmittance of dispersions of oxidized cellulose with different degrees of mechanical treatment was recorded. Scanning electron microscopy (SEM) micrographs and atomic force microscopy (AFM) images of samples prepared from the translucent dispersions showed individualized cellulose nanofibers with a width of about 10 nm and lengths of a few hundred nm. All results demonstrated that more translucent CNF dispersions could be obtained after the pretreatment of cellulose pulp by Oxone (R) oxidation compared with the samples produced without pretreatment. The intrinsic viscosity of the cellulose decreased after oxidation and was further reduced after mechanical treatment. Almost translucent cellulose films were prepared from the dispersions of individualized cellulose nanofibers. The procedure described herein constitutes a green, novel, and efficient route to access CNF.

    Place, publisher, year, edition, pages
    MDPI AG, 2017
    National Category
    Nano Technology
    Research subject
    Engineering Science with specialization in Nanotechnology and Functional Materials
    Identifiers
    urn:nbn:se:uu:diva-328387 (URN)10.3390/molecules22122177 (DOI)000419242400142 ()
    Available from: 2017-08-23 Created: 2017-08-23 Last updated: 2020-02-07Bibliographically approved
    Download full text (pdf)
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  • 7.
    Ruan, Changqing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gustafsson, Simon
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Cellulose nanofibers prepared via pretreatment based on Oxone® oxidation2017In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 22, no 12, article id 2177Article in journal (Refereed)
    Abstract [sv]

    Softwood sulfite bleached cellulose pulp was oxidized with Oxone (R) and cellulose nanofibers (CNF) were produced after mechanical treatment with a high-shear homogenizer. UV-vis transmittance of dispersions of oxidized cellulose with different degrees of mechanical treatment was recorded. Scanning electron microscopy (SEM) micrographs and atomic force microscopy (AFM) images of samples prepared from the translucent dispersions showed individualized cellulose nanofibers with a width of about 10 nm and lengths of a few hundred nm. All results demonstrated that more translucent CNF dispersions could be obtained after the pretreatment of cellulose pulp by Oxone (R) oxidation compared with the samples produced without pretreatment. The intrinsic viscosity of the cellulose decreased after oxidation and was further reduced after mechanical treatment. Almost translucent cellulose films were prepared from the dispersions of individualized cellulose nanofibers. The procedure described herein constitutes a green, novel, and efficient route to access CNF.

    Download full text (pdf)
    fulltext
  • 8.
    Ruan, Changqing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    A green and simple approach for one-pot preparation of an efficient palladium adsorbent based on functionalized 2,3-dialdehyde cellulose2016Conference paper (Refereed)
  • 9.
    Ruan, Changqing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    A green and simple method for preparation of an efficient palladium adsorbent based on 2,3-dialdehyde cellulose2015In: 4th EPNOE International Polysaccharide Conference 2015, 2015Conference paper (Refereed)
  • 10.
    Ruan, Changqing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Preparation of Porous 2,3-dialdehyde Cellulose Beads Crosslinked with Chitosan and their Application in Adsorption of Congo Red Dye2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 181, p. 200-207Article in journal (Refereed)
    Abstract [en]

    Micrometer sized 2,3-dialdehyde cellulose (DAC) beads were produced via a recently developed method relying on periodate oxidation of Cladophora nanocellulose. The produced dialdehyde groups and pristine hydroxyl groups provided the DAC beads with a vast potential for further functionalization. The sensitivity of the DAC beads to alkaline conditions, however, limits their possible functionalization and applications. Hence, alkaline-stable and porous cellulose beads were prepared via a reductive amination crosslinking reaction between 2,3-dialdehyde cellulose beads and chitosan. The produced materials were thoroughly characterized with different methods. The reaction conditions, including the amount of chitosan used, conditions for reductive amination, reaction temperature and time, were investigated and the maintained morphology of the beads after exposure to 1 M NaOH (aq.) was verified with SEM. Different washing and drying procedures were used and the results were studied by SEM and BET analysis. Furthermore, FTIR, TGA, EDX, XPS, DLS and elemental analysis were performed to characterize the properties of the prepared beads. Finally, the alkaline-stable porous chitosan cross-linked 2,3-dialdehyde cellulose beads were applied as adsorbent for the dye Congo red. The crosslinked beads displayed fast and high adsorption capacity at pH 2 and good desorption properties at pH 12, providing a promising sorption material.

  • 11.
    Ruan, Changqing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Favored Surface-limited Oxidation of Cellulose with Oxone® in Water2017In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 64, p. 40600-40607Article in journal (Refereed)
    Abstract [en]

    A novel method for favored primary alcohol oxidation of cellulose was developed. Cellulose pulp andCladophora nanocellulose were oxidized in a one-pot procedure by Oxone® (2KHSO5$KHSO4$K2SO4)and efficient reaction conditions were identified. The effects of the reaction on the morphology,viscosity and chemical structure of the products obtained were studied. The primary alcohol groupswere oxidized to carboxyl groups and the content of carboxyl groups was determined byconductometric titration. SEM, capillary-type viscometry and XRD were applied to characterize theproducts and to investigate the influence of oxidation. For the first time, low-cost and stable Oxone®was used as a single oxidant to oxidize cellulose into carboxyl cellulose. The oxidation is an inexpensiveand convenient process to produce carboxylic groups on the surface of the cellulose fibers and to makethe cellulose fibers charged. Particularly, this method can avoid the use of halogens and potentially toxicradicals and constitute a green route to access carboxylated cellulose. Further, sodium bromide could beused as a co-oxidant to the Oxone® and increase the carboxylic acid content by 10–20%. The Oxone®oxidation is a promising method for oxidation of cellulose and might facilitate the production of CNC.

    Download full text (pdf)
    fulltext
  • 12.
    Ruan, Changqing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    On the preparation of porous 2,3-dialdehyde cellulose beads crosslinked with chitosan and their adsorption of Congo red2017In: Article in journal (Refereed)
  • 13.
    Ruan, Changqing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Preparation of porous cross-linking 2,3-dialdehyde cellulose beads and its application in protein separation2017Conference paper (Refereed)
  • 14.
    Ruan, Changqing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Wang, Zhaohui
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Carbonized cellulose beads for efficient capacitive energy storage2018In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, no 6, p. 3545-3556Article in journal (Refereed)
    Abstract [en]

    Natural biomaterials, including polysaccharides and amino acids, provide a sustainable source of functional carbon materials for electric energy storage applications. We present a one-pot reductive amination process to functionalize 2,3-dialdehyde cellulose (DAC) beads with chitosan and l-cysteine to provide single (N)- and dual (N/S)-doped materials. The functionalization enables the physicochemical properties of the materials to be tailored and can provide carbon precursors with heteroatom doping suitable for energy storage applications. Scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis were used to characterize the changes to the beads after functionalization and carbonization. The results of X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy verified that the doping was effective, while the nitrogen sorption isotherms and pore-size distributions of the carbonized beads showed the effects of doping with different hierarchical porosities. In the electrochemical experiments, three kinds of carbon beads [pyrolyzed from DAC, chitosan-crosslinked DAC (CS-DAC) and l-cysteine-functionalized DAC] were used as electrode materials. Electrodes of carbonized CS-DAC beads had a specific capacitance of up to 242 F g(-1) at a current density of 1 A g(-1). These electrodes maintained a capacitance retention of 91.5% after 1000 charge/discharge cycles, suggesting excellent cycling stability. The results indicate that reductive amination of DAC is an effective route for heteroatom doping of carbon materials to be used as electrode active materials for energy storage.

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  • 15.
    Wang, Zhaohui
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Li, Mingkai
    Hubei Univ, Sch Mat Sci & Engn, Youyi Rd 368, Wuhan 430062, Hubei, Peoples R China.
    Ruan, Changqing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials. Southwest Univ, Coll Food Sci, Chongqing 400715, Peoples R China.
    Liu, Chenjuan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Zhang, Chao
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Xu, Chao
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Univ Cambridge, Dept Chem, Lensfield Rd, Cambridge CB2 1EW, England.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Conducting Polymer Paper-Derived Mesoporous 3D N-doped Carbon Current Collectors for Na and Li Metal Anodes: A Combined Experimental and Theoretical Study2018In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 41, p. 23352-23363Article in journal (Refereed)
    Abstract [en]

    Herein, the manufacturing of a free-standing N-doped mesoporous carbon (CPPY) paper by straightforward carbonization of polypyrrole-coated nanocellulose paper is described. The deposition of Na and Li on these CPPY electrodes, which also serve as current collectors, is studied using a combination of experiments and theoretical calculations. The porous CPPY electrodes gave rise to decreased current densities, which helped to prolong the life-time of the Na electrodes. While the density functional theory calculations suggest that both Na and Li should be deposited uniformly on the CPPY electrodes, the experimental results clearly show that the sodium deposition was more well-defined on the surface of the CPPY electrodes. In contrast to Li, dendrite-free Na depositions could be carried out using deposition capacities up to 12 mAh cm(-2 )and a stable Na electrode cycling performance was found during 1000 h at 1 mA cm(-2). The results suggest that it was difficult to predict the Na or Li deposition behavior merely based on calculations of the metal adsorption energies, as kinetic effects should also be taken into account. Nevertheless, the experimental results clearly show that the use of the present type of porous electrodes provides new possibilities for the development of durable Na electrodes for high-performance sodium metal batteries.

  • 16.
    Wang, Zhaohui
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Pan, Ruijun
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Ruan, Changqing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Redox-active Separators for High-capacity Lithium-ion Batteries2017In: Advanced SienceArticle in journal (Refereed)
    Abstract [en]

    High capacity lithium-ion batteries (LIBs) with good charge/discharge rate capabilities are profoundly needed to be able to meet next decade´s energy demand. Various new cathode materials and electrode engineering technologies that enhance battery performance have been developed, but less effort has been dedicated to improving capacity beyond optimizing the electrodes. We present an electrochemically active separator designed to enhance the capacity and charge/discharge rate capability of LIBs. The thin, mesoporous separator consists of an insulating nanocellulose layer in contact with an electrochemically active polypyrrole-nanocellulose supporting layer. Introducing polypyrrole into the separator i) minimizes the commonly observed “dead weight/volume”, ii) transforms the separator into a redox-active component with a conducting upper current-collecting layer, and iii) increases the pore size and porosity of the separator. In comparison with commercial batteries, our LIB with a LiFePO4 cathode and a redox-active separator shows an enhanced charge/discharge rate capability and a much greater capacity (320 mAh g-1) with respect to the weight of the cathode. Rendering the mesoporous separator redox-active could potentially also boost the capacity and rate performance of other types of lithium-ion batteries as well as electric energy storage devices in general. 

  • 17.
    Wang, Zhaohui
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Pan, Ruijun
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Ruan, Changqing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Redox-Active Separators for Lithium-Ion Batteries2018In: ADVANCED SCIENCE, ISSN 2198-3844, Vol. 5, no 3, article id 1700663Article in journal (Refereed)
    Abstract [en]

    A bilayered cellulose-based separator design is presented that can enhance the electrochemical performance of lithium-ion batteries (LIBs) via the inclusion of a porous redox-active layer. The proposed flexible redox-active separator consists of a mesoporous, insulating nanocellulose fiber layer that provides the necessary insulation between the electrodes and a porous, conductive, and redox-active polypyrrole-nanocellulose layer. The latter layer provides mechanical support to the nanocellulose layer and adds extra capacity to the LIBs. The redox-active separator is mechanically flexible, and no internal short circuits are observed during the operation of the LIBs, even when the redox-active layer is in direct contact with both electrodes in a symmetric lithium-lithium cell. By replacing a conventional polyethylene separator with a redox-active separator, the capacity of the proof-of-concept LIB battery containing a LiFePO4 cathode and a Li metal anode can be increased from 0.16 to 0.276 mA h due to the capacity contribution from the redox-active separator. As the presented redox-active separator concept can be used to increase the capacities of electrochemical energy storage systems, this approach may pave the way for new types of functional separators.

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  • 18.
    Wang, Zhaohui
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Pan, Ruijun
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Xu, Chao
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Ruan, Changqing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Conducting polymer paper-derived separators for lithium metal batteries2018In: Energy Storage Materials, ISSN 2405-8297, Vol. 13, p. 283-292Article in journal (Refereed)
    Abstract [en]

    Overoxidised polypyrrole (PPy) paper has been employed as a mesoporous separator for lithium metal batteries (LMBs) based on its narrow pore size distribution, good thermal stability, high ionic conductivity (1.1 mS cm−1 with a LP40 electrolyte) and high electrolyte wettability. The overoxidised PPy paper was produced from a PPy/cellulose composite using a combined base and heat-treatment process, yielding a highly interrupted pyrrole molecular structure including N-containing polar groups maintaining the readily adaptable mesoporous structure of the pristine PPy paper. This well-defined pore structure gave rise to a homogeneous current distribution which significantly increased the performance of a LiFePO4|Li cell. With the overoxidised PPy separator, a symmetric Li|Li cell could be cycled reversibly for more than 600 h without any short-circuits in a LP40 electrolyte. This approach facilitates the manufacturing of well-defined separators for fundamental investigations of the influence of the separator structure on the performance of LMBs.

  • 19. Xu, Bo
    et al.
    Zhang, Jinbao
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Hua, Yong
    Liu, Peng
    Wang, Linqin
    Ruan, Changqing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Li, Yuanyuan
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Johansson, Erik M.J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Kloo, Lars
    Hagfeldt, Anders
    Jen, Alex K.-Y.
    Sun, Licheng
    Tailor-Making Low-Cost Spiro[fluorene-9,9′-xanthene]-Based 3D Oligomers for Perovskite Solar Cells2017In: Chem, ISSN 2451-9294, Vol. 2, no 5, p. 676-687Article in journal (Refereed)
    Abstract [en]

    The power-conversion efficiencies (PCEs) of perovskite solar cells (PSCs) have increased rapidly from about 4% to 22% during the past few years. One of the major challenges for further improvement of the efficiency of PSCs is the lack of sufficiently good hole transport materials (HTMs) to efficiently scavenge the photogenerated holes and aid the transport of the holes to the counter-electrode in the PSCs. In this study, we tailor-made two low-cost spiro[fluorene-9,9?-xanthene] (SFX)-based 3D oligomers, termed X54 and X55, by using a one-pot synthesis approach for PSCs. One of the HTMs, X55, gives a much deeper HOMO level and a higher hole mobility and conductivity than the state-of-the-art HTM, Spiro-OMeTAD. PSC devices based on X55 as the HTM show a very impressive PCE of 20.8% under 100 mW·cm?2 AM1.5G solar illumination, which is much higher than the PCE of the reference devices based on Spiro-OMeTAD (18.8%) and X54 (13.6%) under the same conditions.

  • 20.
    Xu, Chao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ruan, Chang-Qing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Li, Yunxiang
    Department of Materials and Environmental Chemistry,Stockholm University, Stockholm, Sweden.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    High-performance activated carbons synthesized from nanocellulose for CO2 capture and extremely selective removal of volatile organic compounds2018In: Advanced Sustainable Systems, E-ISSN 2366-7486, Vol. 2, no 2, article id 1700147Article in journal (Refereed)
    Abstract [en]

    A series of sustainable activated carbons (ACs) with large surface areas and tunable pore sizes is synthesized from Cladophora cellulose and its chemically modified derivatives in a one-step physical carbonization/activation process. The molecular structure of the cellulose precursors and the carbonization/activation atmosphere (N2 or CO2) significantly influence the pore structure of the ACs. When using oxidized cellulose and its further cross-linkages as the precursor, the ACs have a large volume of ultramicropores (pore diameter < 0.8 nm). Activation in CO2 results in ACs with surface areas up to 1241 m2 g−1. These ACs have a high CO2 uptake capacity (2.29 mmol g−1 at 0.15 bar, 5.52 mmol g−1 at 1 bar; 273 K) and a high CO2–over–N2 selectivity (42 at 273 K). In addition, the capacity of the ACs to adsorb vapors of volatile organic compounds (VOCs) is remarkable, with values up to 0.97 mmol g−1 at very low VOC concentrations (200 ppmv). The ACs have ultrahigh VOCs–over–N2 selectivity up to 9.35 × 103 at 293 K for 0.02 vol%/99.8 vol% of benzene/N2 mixture. It is anticipated that these ACs will be useful as sorbents for the postcombustion capture of CO2 and for indoor removal and direct air capture of various VOCs.

  • 21.
    Xu, Chao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ruan, Changqing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Li, Yunxiang
    Stockholm University.
    Hedin, Niklas
    Stockholm University.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Porous Polymers and Porous Carbons for CO2 Capture and VOC Removal2017Conference paper (Refereed)
    Abstract [en]

    Porous materials have potential applications in gas capture and storage and heterogeneous catalysis.1 We have developed a series of porous polymers (PPs) and porous carbons (PCs) with high surface areas and tunable pore sizes. They were studied as potential sorbents for CO2 separation and volatile organic compounds (VOCs) removal.2

      The PPs were synthesized by Schiff base polycondensations. The sustainable PCs were synthesized from natural abundant celluloses by a physical carbonization/ activation process. All the PPs and PCs had ultramicropores and displayed relatively high CO2 uptakes (0.93-2.29 mmol/g at 0.15 bar, 2.20-5.52 mmol/g at 1 bar; 273 K) and CO2-over-N2 selectivities (31-90 for CO2/N2 mixtures with 15 vol%/85 vol% at 273 K). In addition, the ACs displayed remarkable adsorption capacity for vapors of VOCs with values up to 0.97 mmol/g at very low VOC concentrations (200 ppmv) and with ultrahigh VOC-over-N2 selectivity (9.35 × 103 at 293 K for 0.02 vol%/99.8 vol% of benzene/N2 mixture).

      The diverse synthesis routes and rich functionalities of PPs allowed further post-modification to improve their performance in CO2 capture. The PPs modified by alkyl amines induced chemisorption of CO2, which was confirmed by the study of in situ infrared (IR) and solid-state 13C NMR spectroscopy. As a result, the amine-modified PPs had a large CO2 capacity and very high CO2-over-N2 selectivity at the CO2 concentrations relevant for post-combustion capture of CO2.

  • 22.
    Zhang, Jinbao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. Monash Univ, Dept Mat Engn, Clayton, Vic 3800, Australia.
    Hultqvist, Adam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Tian
    Monash Univ, Dept Mat Engn, Clayton, Vic 3800, Australia.
    Jiang, Liangcong
    Monash Univ, Dept Mat Engn, Clayton, Vic 3800, Australia.
    Ruan, Changqing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Yang, Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Cheng, Yibing
    Monash Univ, Dept Mat Engn, Clayton, Vic 3800, Australia.
    Edoff, Marika
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Johansson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Al2O3 Underlayer Prepared by Atomic Layer Deposition for Efficient Perovskite Solar Cells.2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 19, p. 3810-3817Article in journal (Refereed)
    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.

  • 23.
    Zhang, Jinbao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Xu, Bo
    KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Chem, Organ Chem,Ctr Mol Devices, SE-10044 Stockholm, Sweden..
    Yang, Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mingorance, Alba
    CSIC, Catalan Inst Nanosci & Nanotechnol ICN2, Campus UAB, Barcelona 08193, Spain.;Barcelona Inst Sci & Technol, Campus UAB, Barcelona 08193, Spain..
    Ruan, Changqing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Hua, Yong
    KTH Royal Inst Technol, Dept Chem, Ctr Mol Devices, Appl Phys Chem, Teknikringen 30, SE-10044 Stockholm, Sweden..
    Wang, Linqin
    KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Chem, Organ Chem,Ctr Mol Devices, SE-10044 Stockholm, Sweden..
    Vlachopoulos, Nick
    EPFL FSB ISIC LSPM, Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photomol Sci, Chemin Alambics,Stn 6, CH-1015 Lausanne, Switzerland..
    Lira-Cantu, Monica
    CSIC, Catalan Inst Nanosci & Nanotechnol ICN2, Campus UAB, Barcelona 08193, Spain.;Barcelona Inst Sci & Technol, Campus UAB, Barcelona 08193, Spain..
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. EPFL FSB ISIC LSPM, Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photomol Sci, Chemin Alambics,Stn 6, CH-1015 Lausanne, Switzerland..
    Sun, Licheng
    KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Chem, Organ Chem,Ctr Mol Devices, SE-10044 Stockholm, Sweden.;Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Johansson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Incorporation of Counter Ions in Organic Molecules: New Strategy in Developing Dopant-Free Hole Transport Materials for Efficient Mixed-Ion Perovskite Solar Cells2017In: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 7, no 14, article id 1602736Article in journal (Refereed)
    Abstract [en]

    Hole transport matertial (HTM) as charge selective layer in perovskite solar cells (PSCs) plays an important role in achieving high power conversion efficiency (PCE). It is known that the dopants and additives are necessary in the HTM in order to improve the hole conductivity of the HTM as well as to obtain high efficiency in PSCs, but the additives can potentially induce device instability and poor device reproducibility. In this work a new strategy to design dopant-free HTMs has been presented by modifying the HTM to include charged moieties which are accompanied with counter ions. The device based on this ionic HTM X44 dos not need any additional doping and the device shows an impressive PCE of 16.2%. Detailed characterization suggests that the incorporated counter ions in X44 can significantly affect the hole conductivity and the homogeneity of the formed HTM thin film. The superior photovoltaic performance for X44 is attributed to both efficient hole transport and effective interfacial hole transfer in the solar cell device. This work provides important insights as regards the future design of new and efficient dopant free HTMs for photovotaics or other optoelectronic applications.

  • 24.
    Zhang, Jinbao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Xu, Bo
    Yang, Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ruan, Changqing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Wang, Linqin
    Liu, Peng
    Zhang, Wei
    Vlachopoulos, Nick
    Kloo, Lars
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Sun, Licheng
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. Ecole Polytech Fed Lausanne, Lab Photomol Sci, Inst Chem Sci & Engn, FSB ISIC LSPM,Stn 6, Chemin Alamb, CH-1015 Lausanne, Switzerland.
    Johansson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    The Importance of Pendant Groups on Triphenylamine-Based Hole Transport Materials for Obtaining Perovskite Solar Cells with over 20% Efficiency2018In: Advanced Energy Materials, ISSN 1614-6832, Vol. 18, no 2, article id 1701209Article in journal (Refereed)
    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.

1 - 24 of 24
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